LEXICAL PHONOLOGY AND SPEECH STYLE: USING A 
MODEL TO TEST A THEORY 
Sheila M. Williams 
Department of Computer Science, University of Sheffield 
Regent Court, 211 Portobello Street 
Sheffield, UK S I 4DP 
email: s.williams@ dcs.shef.ac.uk 
ABSTRACT 
This paper presents LexPhon, a 
computational framework for 
modelling segmental aspects of 
Lexical Phonology (LP). After 
describing the LexPhon system and 
indicating how it may be set to 
represent alternative language 
descriptions within LP, its potential 
application in the characterisation of 
speech style contrasts is 
demonstrated through a small-scale 
study. 
1. INTRODUCTION 
The theory of lexical phonology (LP) 
seeks to explain the inter-relationships 
between morphology and phonology by 
allocating some of the phonological 
processes to the dictionary or lexicon in 
which the morphemes reside. The functions 
of brackets and boundary symbols found in 
other phonological representations are 
subsumed into the framework of the system. 
The domains of both morphological and 
phonological rules within the lexicon are 
subdivided into strata which define both the 
type of morphological process applicable 
and the mode of operation (i.e. whether 
cyclic or non.cyclic) of the associated 
phonological rules. Processes applied on 
early strata are invisible to those of later 
strata through the application of the "Bracket 
Erasure Convention". 
A computational system, LexPhon, has 
been devised to demonstrate the principles of 
LP. LexPhon comprises a level-ordered 
phonological interpreter and a set of 
linguistic tools for reformulating the stratum 
control, developing phonological rule sets 
and for devising phoneme inventories, 
including natural class categorisation tools 
for making explicit the conjunctive 
relationships between the elements of the 
inventories derived. 
Aspects of LP incorporated into LcxPhon 
are the Strict Cyclicity Condition, Bracket 
Erasure and both cyclic and noncyclic 
control mechanisms. Syllabification is 
based on the Maximal Onset Principle and 
fully-specified underlying representations 
are assumed. The number of strata and 
attribution of each stratum to either cyclic or 
noncyclic control is variable by the user. 
Ordered sets of phonological rules are 
allocated to strata. 
LexPhon is used for comparison of 
potential structures for the level-ordered 
frameworks within which the phonological 
rules operate and for alternative formulations 
and assignments of the rules themselves. 
Conclusions can be drawn about the 
effectiveness of each from the broad 
phonemic transcriptions resulting from 
applying any given setting of the system to 
large quantities of data and from the 
processing traces also provided. 
An example is given of the application of 
LexPhon to the study of speech style, using 
data from reported studies of English and 
Mexico City Spanish and its ability to model 
the alternative surface forms evidenced by 
the data, through the re-allocation of the 
same set of phonological rules to different 
strata, is evaluated. 
2. LEXlCAL PHONOLOGY (LP) 
Lexical phonology (Kiparsky, 1982; 
1982b; Halle and Mohanan, 1985, Booij and 
Rubach, 1987; and many others) is a recent 
approach to generative phonology 
(Chomsky and Halle, 1968) in which the 
application of the phonological rules, which 
map from the abstract, underlying form of a 
word to its surface, phonetic realisation, is 
tied to the morphological word formation ~ 
processes taking place. 
Morphological and phonological rules are 
seen as part of the lexicon and are grouped 
into strata. The order of interaction between 
morphological and phonological components 
43 
is stratum-depndant. Thus, LP ties the 
application of phonological rules to 
morphological structure in a particularly 
close way. It provides a highly structured 
framework in which to develop and evaluate 
the rules and representations for 
phonological transformations. However, 
while there is considerable support for the 
theory of stratification of morphological 
rules and the cyclic nature of the application 
of some phonological rules, opinion is 
divided as to the number of strata required 
and the level(s) to which each of the 
identified phonological rules is assigned in 
any given language and further, as to 
whether such higher level control structures 
are universal (Booij and Rubach, 1987) or 
language specific (Kiparsky, 1982, Halle 
and Mohanan, 1985). 
In addition to linear representations, LP 
accounts of linguistic phenomena are 
frequently formulated within the formats 
provided by autosegmental and metrical, or 
nonlinear phonology (for examples see 
Tranel, 1987; van der Hulst and Smith, 
1982; Halle and Vernaud, 1982; Leben, 
1982; etc.). LP descriptions usually adopt 
the two principle tiers from autosegmental 
phonology, the melody and the skeleton, to 
represent the data. Further layers and/or the 
hierarchical representations of metrical 
phonology may be introduced when 
required. 
The melody corresponds roughly to the 
linear representation of segments whereas 
the skeleton carries the positional or timing 
information in x-slots. The x-slots, 
sometimes further distinguished as C and V 
slots, generally correspond one-to-one with 
the segments and are anchored to elements 
of the melody tier. However, in the case of 
long vowels, for instance, two skeletal slots 
may be attached to the same vowel. Empty 
slots and floating segments are also 
permitted by this theory. 
Both morphological and phonological 
higher level structures may be attached to the 
skeleton tier allowing other levels of 
organisation, such as onset and rime within 
syllables, to be represented, if required. 
Nonlinearity of both morphology and 
phonology is incorporated into LP through 
the structuring of the lexicon and the 
independence of syllabification from the 
word-formation process. For LexPhon, the 
concept of timing slots has influenced the 
choice of multiple segment descriptions for 
long vowels and diphthongs. 
44 
Syllabification, where needed, is derived 
from the current segmental representation 
which thus reflects both the melody and 
skeleton tiers. 
However, by permitting features and their 
domains to be independent of the segment, 
autosegmental phonology also allows for the 
description of feature and tonal units smaller 
than a single segment. This aspect has not 
been utilised in the current system. 
3. THE LEXPHON SYSTEM 
LexPhon is implemented in Prolog, using 
LPA MacPROLOG and is based on 
principles of lexical phonology. 
LexPhon is a collection of interactive 
linguistic tools comprising a phonological 
processor, or interpreter, sets of processes 
for creating and updating ph onem e 
inventories, phonological rule-sets and LP 
control structures and investigative tools for 
exploring relationships within the phoneme 
inventory. 
The phonological processor takes as input 
the underlying forms of the morphemes 
believed to contribute to a particular word 
and produces, as output, a broad phonemic 
transcription of the resulting word. To do 
this, the processor applies sets o f 
phonological rules to the developing word 
string, at each level, or stratum, of 
morphological development, in order to 
demonstrate the transformations required to 
produce the attested surface representations 
of the utterance. 
LexPhon allows the user to experiment 
with underlying forms, the structure of the 
rules to be applied, the ordering of the rules, 
their application within cyclic or noncyclic 
stratum control and the definitions of the 
segments to be manipulated. The 
investigative tools allow the segment 
definitions of the phoneme inventory to be 
interrogated to find groups of segments 
answering particular feature descriptions and 
to find alternative descriptions of specified 
groups of segments. 
All the software implemented for 
configuring the processor, updating the 
databases, investigating the properties of the 
selected phoneme inventory and applying the 
processor to the phonological data has been 
collected into a single system which, in 
common with most other Prolog software, is 
of a hierarchical structure. In general, only 
the predicates at the leaves of the hierarchy 
perform direct actions on the data, the 
intermediate levels being present to select the 
appropriate action to be taken. The top level 
of the hierarchy is accessible to the user via a 
pull-down top-bar menu containing five 
sections of commands which control the 
application of the system. 
Fig. 1. Top Bar Menu 
Automatic Dared ... 
Interactive Data ... 
..................... .,.,,,,,. ................. . ....... ..,... ........... o ...... 
Change Control o.. 
Save Control ... 
Load Control .°. 
List Phon Rules 
Change Phon Rules ... 
Load Phon Rules ... 
Delete Phon Rules 
.................... . .......... ..°°.,..,.°.,,..,., ...... .., ........ ,.,., ...... 
List Phonemes 
Change Phonemes ... 
Save Phonemes ..° 
Load Phonemes o.. 
..,..,°,,..,..,.o~,.,...,.°.,,°.,,.,°o..,.,,,,,..,.,.,,..,.,.,,°,.,,.,,,..,,., 
Natural Classes ... 
The first section of the menu holds 
commands which control the application of 
the Interpreter to data. The system can be 
called to process pre-prepared data files. 
These can be selected by name from a 
display menu or, if the user does not wish to 
make an explicit selection, a default set of 
data files can be selected by the system for 
demonstration purposes, on a rota. 
Alternatively, the user may select an 
interactive application, providing the data in 
response to prompts by the system. 
Alterations to the Control Structure, the 
Phonological Rule database and to the 
Phoneme Inventory may be made through 
the commands provided in the second, third 
and fourth sections of the control menu, 
respectively. Commands are provided to 
allow the user to list the phoneme and rule 
descriptions represented by the appropriate 
sections of the database and to alter or 
45 
replace them as necessary. The Interpreter 
commands may then be called to 
demonstrate the effects of the changes. 
The commands provided in the last 
section of the menu allow the user to 
investigate relationships between the 
members of the current Phoneme Inventory. 
The user can choose to analyse this database 
by entering a list of segments by name and 
receiving one or more categofisations by 
common feature values or by entering a list 
of features with associated values and 
receiving a list of all segments in the current 
inventory which satisfy those values. 
3.1 Representations 
There are basically four different types of 
data upon which the processor must operate. 
The first and most obvious one is the word 
string, the representation of the word itself at 
each of its levels during the word formation 
process. Associated with this is the 
phoneme representation, as each of the 
fundamental segments, or phonemes, which 
make up the word string has a complex 
structure which serves to establish its 
relationship to all the other phonemes used 
by the language under study. 
Within the theory of LP both 
phonological rules and strata have 
paramount significance because it is through 
their interaction that the surface alternations 
between morphologically related words of 
the language are explained. 
Although the representation of the 
affixation process is itself inherent in this 
interaction process, an affix morpheme 
representation has also been devised for 
LexPhon, to enable the user to dictate the 
levels at which affixation data is 
incorporated into the word string when the 
full underlying form is presented to the 
system by means of a data file. 
3.1.1 Phonemes 
Phonemes are represented by simple 
predicates of two arguments, the name, 
which is a phonetic character, and the feature 
specification. The phoneme inventory is 
fully-specified for all the features used by 
Halle and Mohanan (!985) in their 
description of LP for English. The 
specification is implemented as a list of 
negative and/or positive value elements to be 
matched against a list of feature names to 
obtain the complete description. This means 
that 2-valued logic ~s c~,ploy~ ~ queW t~e 
database. 
Two separate lists of feature ~raes are 
available so that vowels can be specified for 
tenseness whereas consonants are specgfied 
for stridency. This is a co:~p:o:~:~s~ ~zkzt~9~ 
to balance the objectives c~ ~ct ~r.ovi,$~ng 
values for irreleve.nt fea~,~':~s, wkE~ a:Y=e~::~:~ 
as closely as possible tc X~e ~ba~u~e ~e~ 
employed by Halle arid ~¢~har,~an, and ~i~.e 
computational efficiency oblained by having 
both the minimal number of features and 
feature matrices of the same dimensior~s for 
all segments and r~.ay ke~vc ~r~gu~'.~t~c 
implications (Wi~ia~z, ~.~>~. ...... 
Example of vowel: 
anterior, -high, +tow, -buck, 
-round,-nasal, +cont~nuant, 
+voiced, -tense. 
Example of consonant: 
-syllabic, "~- c ~.~ ~ ~ ~~ ~ ~ ~ 
anterior, +high, -low, -back, 
-round, -nasal, -can'~nuant, 
-voiced, +strident 
Vowels do not have ~ fee.Sure 
specification for length as a~ ~he v~wc~s ~n 
the inventory are 'short ' and 'pure '. 
Diphthongs and long vowels are represented 
as two consecutive segments. 
If the application of a phono\[eg~cal ruse, 
whose conditions are ofi~e~.~ ~a~!sfied, 
would result in the fcr~a~c~, c~' r.. seg~c~* 
with a feature description which does hoe 
currently appear in the phoneme ~avemory 
then the segment is created and added to the 
inventory. The name for the new ~%~nent ~ 
generated by concatena1~,g ~7~?: ~f ~e 
segment to which ~ransfo~.~\[ena were 
applied in order to construct i~, wit~ a un~3~e 
number. This enables the user ~ be abte to 
trace the processes whack ~ed to its 
formation. 
3.1.2 Word Strings 
Word Strings are ordered lists of 
elements which represent the current state of 
the word form, or working string, at any 
stage of the derivational process. 
e.g. 
46 
:: (i:~,~ ~:~ ~,~ ~ ~ba u nd a ry\] 
~c~:on to segment names for each 
p~::.~:~c.~ !'cT7.:e.e~t*d, t~.e word string may 
c ............. , ~&.,.~, ....... c~o,~ary markers and 
:.:..~.:~.~:~ ..... ~f~::.xat~on which has 
,~.~ ........ ~ ....... ":~ .... ~"~ ~u~ent stratum. Each 
s~:.':: =:. ~:=:~ ~.c~::, ~:.~ application predicate 
wi~:L:::. ~ ~:~:um ~akes an input string and 
ins~nt~,atcs a variable to the string which is 
the ~:c~ul~ of its application. The 
pb.o~.~,~t ~¢, 'p~Ie', predicates operate 
........ ~'~<"~ of :k~ current word string EFt, ~', .: ............... 
w~,f.c~,7. ~5~:.~ ":~:. ~.~ context required by 
:~...~, ..~.:~r~. ~e result of their 
t~c~:.:.:.~.~f.~z .~ ~ ~ec:acemcnt word stnng 
~,=~'i~ ~f~r ~ ~ffixation at 
~~: 2 = \[wordboundary, 
~ t, ~, ~, ~, ~ordboundary\] 
~; ........ ~ .... ~"~'~'~*"~ ~'~|~ " £ -) I = 
..... ~ ~:-,,o ::.~ :% n, n, n, p, p, 
~" ~!, ~ i'. (;~ ~ = \[I, I, n, 
T~is vowel-shift rules applies when its 
co~en~ ma~chc~ ~ two instances of the same 
V@V.~3~ ~ ~ ~ " ~5c ..... ~ ~ each other. In this 
c.~: ....... .~ ...... , %.:~ ~.p~es to vowels which 
7~,,,, ~ ~ ~ ~:~ ,,_~.~, 0:.~o~ c:~,~=~ ~e~¢ value of the feature 
IdA. T~C 1~, c:m.r .high becomes +high or 
+,~iJ~ ~-~.~.~,,~ ...... ~i~h. The replacement 
seg~.¢~:~ ~ cre~ed by applying a 
' ...... ~ ....... ' ~#~"~ which takes the value 
....... ~.,,::,, .... ~atches the context 
~::.~ ~. ~.~.~ c. c:~..~z~ges, in this case £, \[high, 
p~. ,.,.~,~ ~,~ f~ is 'p', for positive, 
..... ~'~ ° f~= high in E is 'n' (for 
The °r~ccns~c~' predicate reports the 
l~ 9f both ~n~ source phoneme (£ in this 
ex~p~e) and the resulting phone which it 
haa created (x in this example) and lists the 
full set of feature values for the new phone. 
If the phone matches a description in the 
current phoneme inventory, its label is the 
name of that phoneme. Thus, in the output 
of both the rule (shown as the partial string 
beginning with the start of the context) and 
the stratum, two instances of the phoneme x 
replace the two instances of the phoneme E 
found in the input string. 
In the case of data provided from data 
files, the word string may also contain 
atomic elements representing word and 
compound boundaries and affixes to be 
applied at particular strata. The actual 
working string(s) consists of any 
consecutive sequence, within the word 
string, of segment names and 'new' 
boundary markers (i.e. the boundary 
markers which denote junctures within the 
current stratum). 
e.g. 
lwordboundary, 
compboundary, g, r, c, c, n, 
compboundary, h, ~, ~, s, 
compboundary, los2, nE:s2, 
wordboundary\] 
The level of affixation of an atomic 
morpheme is denoted by a number 
concatenated to the end of the string of 
segments which represents its underlying 
form. This is matched to a list of potential 
affixation types which forms one of the 
parameters to each stratum definition 
predicate. Markers denoting compound 
boundaries must be inserted before, between 
and after, the lists of elements defining the 
components to be attached by compounding, 
to ensure that associated affixes are 
conjoined in the correct order. In this case 
more than one current working string may 
be being processed at any one time within 
the word string. 
As with the interactive word string 
representation, an atomic structure called 
'new' is included in each affix segment list 
when the affixation process takes place and 
the morpheme is expanded into its 
component segment names, to provide an 
explicit juncture which may be required for 
the context of some of the phonological 
transformation rules. 
e.g. 
\[wordboondary, g, r, ee, x, n, 
Dew, h, a, o, s, new, 1, c, s, 
new, n, E, s, wordboundary\] 
These extra items are deleted at the end of 
the stratum in which they are introduced to 
47 
ensure that the junctures from that stratum 
arc not visible to later strata. 
3.2 Phonological Rules 
Phonological Transformation Rules may 
involve replacement, transposition, deletion 
or insertion of segments. 
Each rule is represented in the data-base 
by a Prolog predicate with six arguments. 
e.g. 
prule(3, \[I, s, xl Rest\], \[x, z, xl 
Rest\], 's -> z / z ... x . ', 
scc, nsyll):-!. 
The first parameter is the rule number " 
which is used in rule ordering and in 
allocation of rules to strata. The second and 
third parameters represent the string to be 
replaced by the rule and the substitution 
string respectively. Each consist of a list of 
one or more phoneme names (and possibly 
new morpheme boundary and/or syllable 
boundary atoms) or variables, designating 
the segments undergoing transformation and 
their contexts, and a list variable to be 
instantiated to the remainder of the working 
string. The list variable ensures that the 
remaining part of the word list, which has 
not taken part in the transformation, is 
maintained in its current form as part of the 
word list. 
Where a segment is represented by a 
variable or a feature bundle, the predicate 
will normally have one or more clauses to be 
invoked to satisfy the conditions on that 
segment. Thus, in the general case, the head 
of the prule predicate will be followed by a 
list of clauses representing the conditions to 
be satisfied in order for the rule application 
to succeed and the operations to be 
performed to instantiate all the relevant 
information for its consequences to be 
implemented. 
e.g. the diphthongization rule 
prule(46,\[Phon,Phon l Rest\], 
\[Phon,NewphoniRest\], 'V -> 
\[+high,-low,ixround\] / \[V, 
+vowel, txback,-high\] .... ', 
scc, nsyll) :- 
feature(Phon,consonant al,n), 
alpha(back,Val,Phon), 
feature(Phon,high,n), !, 
reconstruct(Phon,Newphon, 
Features,\[high,p,low,n,round, 
• Val\]). 
Each rule also has a parameter which is 
the atomic form of the linguistic description 
of the rule. This is used for display 
purposes in listing the rule and, in the case 
of a rule which has been generated 
interactively, will be the actual string from 
which the rule has been generated by the 
system. 
The last two parameters which must be 
specified for each rule denote whether it 
obeys the Strict Cyclicity Condition and 
whether it requires that the string to which it 
is to be applied has been syllabified prior to 
application. The SCC marker must be set 
explicitly by the user when generating the 
rule but the syllabification marker will be set 
automatically during interactive rule 
generation if the context for the rule contains 
a syllable boundary marker. 
The rules in phonological rule database 
are explicitly ordered by means of their 
identifying numbers. Phonological rules can 
be represented disjunctively in the database, 
if necessary, by asserting a series of rules in 
the Prolog code, all allocated to the same 
rule number. 
Explicit variables can be attached to 
segments to indicate that two or more 
segments must be identical in a particular 
context. 
An interactive rule interpreter is provided 
which accepts a wide range of input formats 
including segment labels, feature bundle 
descriptions, or-notation and segment 
variable labels and translates the linguistic 
formulation of a phonological rule into 
Prolog predicates which implement it. 
3.3 The Control System 
After accepting the root form, the 
interactive control system calls the stratum 
control mechanism to act upon the working 
string by recursing over the current stratum 
definitions until all the processes associated 
with each of the strata defined have been 
applied. A similar mechanism is 
implemented to operate upon data predicates 
read from data files. These mechanisms are 
implemented by means of tail recursion. 
Failure of the main predicate which defines 
the control mechanism allows a second 
predicate to be invoked. This will always 
succeed, returning the current value of the 
working string as the value of the result 
variable. 
Each call to the stratum control 
mechanism is invoked with the stratum 
number variable already instantiated. Thus, 
the top-level call passes 1 as the stratum 
number for the first level of processing. 
eg. the control predicate which governs 
processing for data input interactively has 
the following definitions: 
do_all_strat(Number, Input, 
Output):- 
stratum(Number, First, Last, 
_, Cycle), 
do-strat(Number, Input, 
Nextstring, First, Last, _, 
Cycle), 
I 
Nextnum is Number + 1, 
do_all_strat(Nextnum, 
Nextstring, Output). 
do_all_strat(_, String, String). 
48 
and is initially called with Number 
instantiated to I and Input instantiated to the 
wordlist consisting of the segments of the 
root morpheme. 
Assuming that a stratum I exists in the 
current control structure (ie. that there is at 
least one stratum in the currently modelled 
system), this stratum definition is matched 
by the first clause which thereby instantiates 
all the variables necessary to implement the 
processing of the first stratum. These 
variables are then passed to another predicate 
'do_strat' which carries out the processing, 
returning the final state of the working string 
at the end of the stratum, instantiated to the 
variable Nextstring. The number of the next 
stratum is then calculated and this is then 
used, together with the value of the current 
working string, to call the next stratum by 
re-applying the same predicate. This 
continues until the 'stratum' predicate fails to 
match, indicating that no further strata have 
been defined for this model of lexical 
phonology. 
The first predicate of 'do all strat' then 
fails also and the second predicate is then 
invoked, always succeeding, associating the 
value of the current working string (Input) to 
the Output variable of this last stratum call. 
This is instantiated to the Output variable in 
the call which generated it and thus 
instantiated to the Output variables in all 
previous calls by being passed back as the 
value of the final variable in each call. Thus 
the value of Output returned from the first 
call to the 'do all strat' predicate is the same 
as that of the working string (Nextstring) at 
the end of the last call which found a new 
stratum to apply. 
As each call to the stratum control 
mechanism is invoked with only the stratum 
number instantiated, it must first attempt to 
unify the remaining control variables in the 
call with the associated values in a predicate 
of the stratum definition database which 
defines the stratum identified by that 
number, if such a stratum exists. If no 
matching predicate is found for this level 
then the call succeeds without further 
recursion by means of the second control 
predicate. 
Further processing is then carried out to 
convert the working string from the list 
form, in which the segments may be 
individually manipulated, to a character 
string. At this stage all the segments in the 
list should be symbols representing 
phoneme names. The resulting string 
represents the broad phonemic transcription 
which is the product of the Processor. 
e.g. 
Phonemic Transcription: 
sizzInlrJ 
In the case of data supplied from file, it 
may happen that, if affixation processes 
which can only be resolved at later strata 
separate affix atoms for earlier strata from 
the root form, then these earlier affixes will 
never be resolved. Also, if the application 
of a phonological rule involves a 
transformation upon a segment which results 
in the creation of a new segment not listed in 
the current phoneme inventory, segment 
descriptors may remain in the working string 
at the end of processing. In either of these 
cases, an appropriate message will be 
generated and the working string will be 
displayed in its list form in place of the 
phonemic transcription which results from a 
completely successful application of the 
system. 
e.g. 
Unresolved atoms in t h e 
final working string 
\[wordboundary,compbounda 
ry,s,p,o,o,n,s,compboundary, 
f,u,l,compboundary,wordbou 
ndary\] 
The phonological rules are applied, in 
numerical order, in blocks defined by the 
stratum definition predicates. These blocks 
must each contain a contiguous set of rules 
from the current data-base, the only 
restriction being that the last rule number 
specified must be the same as or higher than 
the first rule number. Thus, blocks may 
overlap and the rules attached to a later 
stratum need not be defined later than those 
attached to earlier strata. Although rules are 
applied ordinaily within each stratum, there 
is no requirement that a rule must be defined 
for every number within the range of that 
stratum. 
3.3.1 Control Mechanisms 
Cyclic and noncyclic Stratum Control 
Mechanisms are defined and govern the 
ordering of morphological affixation and 
phonological transformation phases for each 
stratum. 
For cyclic application, the relevant rules 
for the stratum are applied to any appropriate 
contexts in the current working string, 
subject to the SCC condition which prevents 
application of any rule which has been 
marked for SCC, on this cycle, and then the 
appropriate morphological affixation process 
is invoked. For interactive use, an interface 
is provided to elicit and validate the data in 
the correct format. Data supplied from a 
datafile is validated and checked against the 
stratum information to ensure that the current 
stratum is an appropriate level at which to 
incorporate it into the word string. 
Following every subsequent affixation at the 
same stratum, the phonological rules 
assigned to that stratum are reapplied. 
In non-cyclic strata, all affixation takes 
place before the associated block of 
phonological rules is applied, once only, to 
the outcome of the affixation process. 
To complete the implementation of the 
control strategies described in the Halle and 
Mohanan paper, for stratum 3, the 
compounding level, the cyclic control 
mechanism has been expanded for the 
default model. If compounding takes place 
then stratum 2 is re-invoked to test for 
further morphological affixation before 
completing stratum 3 and, if this occurs, 
both the morphological and phonological 
components of stratum 2 are re-applied. In 
49 
the Halle and Mohanan model, the only 
possible morphological process at stratum 3 
is compounding. 
However, in order to make the system as 
flexible as possible, the 'hmspecial' 
predicate set, which controls the order of 
application of morphological and 
phonological processes, has been extended 
to include all types of affixation normally 
possible, in parallel with the normal cyclic 
control mechanism. Only compounding 
causes the loopback mechanism to be 
invoked even if other classes of affixation 
have been authorised at stratum 3. The 
loopback mechanism returns the current 
working string unchanged if no affix is 
found but invokes the phonological rule 
predicate followed by the normal 'cyclerule' 
predicate if affixation has been successful. 
This enables further affixation to take place, 
if necessary, cycling through stratum 2 for 
each affixation process. 
As this is an extension to the stratum 3 
affixation process, no bracket erasure takes 
place between the two strata during the 
looping process. A single application of the 
bracket erasure predicate is invoked only on 
final completion of stratum 3, i.e. when 
there is no further compounding and no 
further stratum 2 affixation to be processed. 
This means that all the 'new' conjunction 
atoms introduced at both stratum 2 and 
stratum 3 are available throughout this 
operation. 
This mechanism raises many theoretical 
problems. However, the objective of its 
implementation in LexPhon was to ascertain 
the closest possible correspondence to the 
descriptions provided by Halle and Mohanan 
(1985) in order to explore its consequences, 
so it is sufficient to note here that practical 
demonstrations (Williams, 1993) indicate 
that the loopback mechanism is 
unnecessarily cumbersome and does not 
achieve the consequences predicted for it. 
The Halle and Mohanan description was 
chosen as the default model as it is both the 
most complex and the most completely 
specified model of LP available. Other 
descriptions of LP were taken into account 
in trying to make LexPhon sufficiently 
flexible to be utilised in contrasting a wide 
variety of approaches to LP. 
In addition to being a tool for developing 
linguistic descriptions, it is intended that the 
processor should itself be a model of the 
control structures of LP. 
Although the system has not yet been 
applied extensively to languages other than 
English, one of the fundamental tenets 
common to the various approaches to LP is 
that the mechanisms which apply the rules 
are language independent but that the 
phoneme inventory, the morphological and 
phonological rules and the number and 
cyclicity of the strata are language dependent 
(Kiparsky, 1982; Halle and Mohanan, 1985; 
but see also Booij and Rubach, 1987, for 
universal model of stratification). The 
system has been developed to reflect this 
view with the modules which represent the 
phoneme inventory, the rulebase and the 
stratum definitions being independent and 
interactively changeable. This also 
facilitates comparisons between alternative 
models of the same language. 
3.4 Summary of the LexPhon default 
model. 
The default phonological interpreter is 
based on Halle and Mohanan's (1985) 
detailed description of LP which provides 
for a framework of five strata, four of which 
operate within the lexicon. The postlexical 
and second lexicai strata are noncyclic, all 
other strata being cyclic in application. 
Although fundamentally cyclic, stratum 3, 
the level at which compounding takes place, 
has a much more complex structure allowing 
for backtracking to stratum 2 under specific 
circumstances. LexPhon can b e 
reconfigured by the user to provide for 
potentially any number of strata, each of 
which must be designated as cyclic or 
noncyclic. 
The default databases of the LexPhon 
system comprise the phoneme inventory 
containing the 42 phonemes listed above, 24 
of the rules suggested by Halle and 
Mohanan (1985) and the five stratum model 
also proposed by Halle and Mohanan. 
Descriptions of the current state of each 
database can be invoked from the LexPhon 
system menus. The default definitions are 
summarised in the tables below. 
The segment label /y/appears in the 
defailt phoneme inventory so that the Halle 
and Mohanan rule specifications could be 
matched as closely as possible for the default 
rule set. It is exactly equivalent to the IPA 
symbol /j/more commonly used for the 
same feature specification. 
50 
coronal 
anterior l 
high 
Table 1: Phone(eme) definitions 
I x I' l, lulul,lol l o o =, a, o 3, o y w r, l t 
=onsowtallnlnlnlnlnlnlnlnln n . n n n n n n n p p p 
so.o=t Ipilp \[P IP IP IP IP IP IP P P P P P P P P P P P P 
syllabic \[P JP i p\[P \[P iP IP IP IP i P P p p p p p n n n n n 
I n Inlnl. lnlnlnlnl n n n n n n n n n n p p p 
I n I. Inlnlnlnlnlnl n n n n n n n n n n n p p 
Ip \[p \[p \[p \[p \[n in \[n \[n i n n n n n n n p p n n n 
low I n I n In In I n I n I n In I n n p p p p p n n n n n n 
back \[n \[niplpip\[ninlplp p n p p p p n n p n n p 
~ou~d In I. \[ n\[p \[p In In In \[p p n n n p p n n p n n n 
in Inlnlnlnlnlnlnln n n n n n n n n n n n n 
continuant IPlIP \[P I p I p IP IP \[P IP P P P P P P P P P P P P 
voiced IPll p\[p \[p Ip I p\[p \[p I p p p p p p p p p p p p p 
strident/tenseln IP In In IP In IP In In p n n p n p n n n n n n 
consonantal \] 
sonornllt 
m syllabic i 
eomnsJ 
anterior 
high 
low 
back 
round 
continuant 
voiced 
strident/tense 
HCH\[igDl\[llmDmn l  
II.,..,..,==.,..,-.,..,-.,-.,.nD 
l=,l =,l m.~ i ~ n.~ =,l e.~i.~ iz,l e.ll\[ ~ 
l-,l I ~,!111 I~,!1 .,l I~,ll I:,ll I I -,l -,l~! 
3"-"="-"="-"="="-"="=II Ii,l.,-.,--.,-.,--=,-.,-.,--=,-.,-ll~ll 
i-,--,-.,-.,--,-.,-=,-.,--,-llll I 
,~im i ~l i ~li~l i.~ll~i n ~ii.~l,~-,l\[\] 
llllllllbl/l~l~l/ll~lll\[\] 
Key: n = negative, p = positive. 
Table 2: List of Phonological Rules with Linguistic Form 
Rule \] Descriptio n 
12 CiV Lengthening 
13 s-Voicing 
14 Trisyllabic Shortening 
15 /c-Shortening 
16 /-Shortening 
3o Velar Softening 
31 Nasal Assimilation 
32 g-Deletion 
33 Prenasal ~Deletion 
34 n-Deleti0n 
35 Non-coronal Deletion 
36 Vowel Shift: Rule 1 
37 Vowel Shift: Rule 2 
3S Z.Lowerin8 
Rule Formulation H&M ref. 
0 -> A / lA,-hlgh,+vowel\] ... \[+vowel, +hlgh,-ba¢k\] & 57 
51 
s -> z / \[U,+uowell U ... & l+uowell \] \] 
A -> 0 / \[A,tvowel\] ... ll,3,-vowell \[*vowell It,3,-vowel\] l*vowel\] 56a 
R -> 0 / \[R,+vowal\] ... \[l,3,-vvwel\] &,l,k 56C 
! -> 0 / t ... \]-syllabic\] & y l+syllobic\] \] lO 
i*volarobstruant\] -> i*coronal,+anterior,-hlgh,-low,-back, 64 
+contlnuant,*strldont\] / ... \]+uowel,-bock,-Iow\] 
\[+nasal\] -> q / .. \[+uelarobstruent\] \] \] 
\[*nasal\[ -> m / ... \[*bilabial\] 
g -> 0 I i+nasal\] ... & |2 
g -> A I \[A,+vowell ... \[+nasal\] & \]06a 
n -> o I \[+nasal\] ... & \]06h 
\[*obstruent,+volced,-coronal\] -> 0 I i*nasal\] ... & \]06C 
\[A,+vowel,-low,ochlghl R -> \[B,-o~hlgh\] e 6\] 
\[R,+vowel,-hlgh,51ow\] R -> \[e,-plowl 8 6\] 
! -> \[-high\] I \[-syllabic\] ... \[+consonantal\] 9,4~L 
39 
40 
41 
42 
44 
45 
46 
90 
96 
98 
/-Lengthening 
Spirantization 
y-Insertion 
Palatalization 
~Deletion 
0 -> O / \[-sylleblc\] \[U,*vowei,*hlgh, +back.-roundl ... \[-syllabic\] 
\[+obstruent,+coronal\] -> \[+conUnuant, .strident\] / \[*sonorant\] ... y 
\[.obstruent,.coronal\[ -> \[*contlnuant, .strident\] / \[-conUnuant\] ... 
0 -> y / \[.consonantall ,.. \[*vowel, .hlgh,*back,-round\] 
\[.obstruent,+coronal\] -> \[-anterlor,+hlgh, -low\] / ... 
y -> 0 1 \[*coronal,-anterlor\] ... 
95 
85 
93 
80 
81 
Vowel Reduction u -, o / \[u,-vowe,\] ... r 
Dipthongization u -> \[+hlgh,-Iow,~roundl / \[U,*uowel, ~back,-nlghl ... 62 
/-Rounding \[÷uowel,+hlgn,.bock\] -> \[*roundl 94b 
0 -> v / IV,+mld,+roundl ... I \[-synnblcl 144 
A -, 0 / ... In,-uowell 124 
o-Lengthening 
Degemination 
Table 3: Allocation of phonological rules and 
control mechanisms to strata 
Word-derivation \[ Associated Halle & 
Level \[ Phon. Rules Mohanan model 
+-derivation and 10-19 1. cyclic 
inflection 
#-derivation 30-59 
compounding 60-69 
post lexical 
#-inflection 70-79 
90-99 
2. noncyclic 
3. cyclic with 
loop-back to 2 
4. cyclic 
5. noncyclic 
Each of these databases can been updated 
using the dialogue-based database 
development tools incorporated in the 
LexPhon system. 
Thus, LexPhon can be applied to the 
comparative study of alternative control 
frameworks, varying in number and/or 
cyclicity of strata, for any particular 
language description; to the development of 
phonological rule-sets and comparisons of 
allocations of rules to strata and to the 
investigation of particular phonological 
phenomena. 
An example of the last case, involving the 
characterisation of regular variation between 
speaking styles is presented to illustrate how 
the LexPhon system can be applied to such a 
study. 
4. SPEECH STYLE STUDY 
The term "speech style" usually refers to 
intra-speaker variation although there is not 
as yet any consensus as to its scope 
(Llisterri, 1992). Definitions and 
categorisations may relate to the context in 
which the speech occurred (formal/ 
informal); to the task involved in producing 
the speech (read/descriptive/conversational); 
to the speed at which the speech is produced 
(rapid/slow); or to the amount of attention 
52 
believed to be directed to the speaking 
process (casual/careful). Stylistic variations 
may be restricted to prosodic, phonetic and 
phonemic contrasts or extend to syntax, 
choice of lexical items or even choice 
between different languages (Milroy, 1987). 
Thus, speech style may be seen as a single 
continuum along which each of the 
contributory factors may be ranged (Labov, 1981) 
or as a set of distinct categories within 
which there can be intra-style variation 
(Milroy, 1987). Further, different factors 
can result in the same phonemic or phonetic 
contrasts (Kreidler, 1989). 
Harris (1969) presented a study of 
Hispanic phonology in which he contrasted 
the regular variations in pronunciations 
which occurred, relative to the speed at 
which each utterance was produced. He 
identified four different speeds which could 
be characterised for the Mexico City dialect 
of Spanish under study. These comprised: 
Largo, slow and also described as 
overprecise; Andante, not quite so slow and 
considered typical of natural careful speech; 
Allegretto, somewhat faster and typical of 
natural casual speech; and Presto, extremely 
fast and unconstrained. 
The styles are distinguished b y 
differences in nasal and sibilant assimilations 
as well as by other variants. The assimilation 
phenomena seem to be at least partially 
dependent on differences in the level of 
boundaries which must be specified in the 
phonological rules. This suggests that the 
level ordering of LP might enable a simpler 
characterisation of speech style contrast be 
formulated. 
Although Harris defines style in terms of 
speech speed he assumes a direct correlation 
between this and the level of attention or 
carefulness applied to speaking. Both the 
amount of care taken and the degree of 
precision with which an utterance is formed 
are hypothesised to decrease with increases 
in the rate at which the utterances are 
produced. Hence, this comparison explores 
variations in the pronunciation of the same 
utterances under varying conditions of 
speech speed and/or carefulness. It is 
contrasted with a similar study of reported 
casual versus more careful and/or formal 
forms in British English. 
4.1. The Hispaoic Study 
The nasal-assimilation and s-voicing rules 
suggested by Harris (1969) are applied to 
underlying forms in the context of a level- 
ordered LP of Spanish, together with the 
vowel-glide transformation rule which feeds 
the nasal and sibilant assimilation rules in 
certain contexts. Thus, certain adjustments 
to the Phoneme Inventory were required. In 
addition to language-specific differences in 
the phoneme inventory, Harfis's treatment 
of the Mexico City data explicitly rescinds 
the distinction between phonemic and 
phonetic levels. The voiced velar fricative is 
needed and Harris posits several additional 
nasal symbols to support his account. In 
total, he suggests three underlying nasal 
segments and an additional four nasal 
variants which appear in surface forms of 
the Mexico City data. 
4. I. I The Hispanic Phoneme Inventory 
In principle, there is no limit to the size of 
the phone/phoneme inventory in LexPhon. 
However, in the current system the feature 
set from which the phonemic segments are 
created is fixed and some processes can only 
operate upon Single character labels. In 
addition to 'coronal', 'anterior' and 'back', 
Harris employs the feature 'distributed' to 
distinguish between the Hispanic nasals. 
This is not currently available in LexPhon. 
Thus, the full set of nasal segments available 
for the Spanish speech study, and the 
features over which they vary, were as 
follows: 
Table 4: The Hispanic nasals 
rn n fi q fi 
coronal ÷ ÷ 
anterior + + 
back - + 
\[high ! + 
where /m/,/n/ and /fi/ are the 
underlying nasals and/q/ and/fi/ are 
respectively the velar nasal and the additional 
'+coronal', '-anterior' nasal, hypothesised 
by Harris, to be present and distinct 
although acoustically indistinguishable from 
the alveolar/n/. Each of these has been 
allocated a single character label whose 
appearance in the LexPhon display font is 
the corresponding IPA character. 
The phoneme inventory was updated first 
to ensure that any segments which might be 
required for rule definitions would be 
available. This is important as the rule 
interpreter has data validation mechanisms 
so that, at the time of input, all segment 
labels must refer to segments within the 
current phoneme inventory. 
4.1.2 The Hispanic Rules 
Since rules in cyclic strata must relate to 
derived forms, whereas rules in non-cyclic 
strata are not permitted to refer to embedded 
boundaries, two forms of the s-voicing and 
nasal-assimilation rules were derived. 
The vowel-glide transformation rule must 
be formulated with respect to new derivation 
at the start of its context, so only one formis 
required as it is neither cross-boundary nor 
word-formation independent in its action and 
can therefore apply at any stratum. It must 
precede both nasal-assimilation and s- 
voicing, as it feeds both rules. 
I I = \[ -consonantal, +high, - 
tense\] -> \[-syllabic\] / &_ 
\[+syllabic\]. 
Harris provides a series of possible 
definitions for the nasal assimilation rule. 
The rule context includes various alternative 
boundaries or optional boundaries at 
different speech speeds. Additionally, for 
fast speech (e.g. Allegretto), Harris requires 
extra constraints on the nasals to ensure that 
/ m/ is unaffected before /n/, and to 
account for nasal assimilation to word-onset 
glides. 
14 = \[nasal\] -> \[ixcoronal, 
13anterior, 1~back, 6high\] /_ 
& \[-sonorant, ixcoronal, 
~anterior, ~back, fihigh\]. 
22 = n -> \[txcoronal, 5high, - 
13anterior, Kback\] / _ \[- 
53 
syllabic, o<coronal, 13high, 
• 3back\]. 
Fors-voicing, Harris provides only one 
form which varies with speech speed, only 
in whether boundaries or optional 
boundaries need to be defined. 
16 = s -> \[voiced\] /_ & \[- 
syllabic, voiced\]. 
24 = s -> \[voiced\] / _ \[- 
syllabic, voiced\]. 
The Hispanic Rule database was formed 
by first selecting the "Delete Phon Rules" 
option from the top-level menu, to clear the 
database and then adding each of the above 
rule formulae interactively via the "Add a 
Rule" dialogue selected from the "Change 
Phon Rules" menu. 
4.1.3 The Hispanic Data 
As Harris had identified a style-dependent 
variation between article-noun boundaries 
and the boundaries between less primitive 
constituents, it was necessary to represent 
this in the data and adapt LexPhon to cope 
with utterance construction beyond word 
level. In this case, as the lowest level word 
boundaries involved only monomorphemic 
definite and indefinite articles, it was derided 
to treat these as an additional word-internal 
level and reserve the word boundary symbol 
to designate phrase boundaries and higher 
level constituent boundaries. 
As the plural morpheme consistently 
occurs after other possible suffixes, I have 
assumed at least two word-internal levels. 
Thus, most word internal affixes were 
designated type 1, inflectional affixes were 
designated type 2, definite and indefinite 
articles were designated type 3 and phrase 
boundaries were identified by the word 
boundary symbol. 
Three sets of data were selected to include 
as many cases as possible of nasal and As/ 
segments in contexts selected to contrast the 
same underlying phoneme string with 
different boundaries for as many different 
phoneme sequences as possible. 
A total of 76 words or short phrases were 
included • in the databases tested on all five 
settings of the system. They were selected 
Io provide as many contrastive contexts as 
possiblc with examples for each level of 
boundary wherever possible. A selection of 
these are shown below. 
54 
Table 5: Examples of Hispanic data 
\[word(s) \[ underlying form I translation 
wb,d,t,s,d,c,Wb since 
desdefiar wb.d¢,1.a.t.n.orl.wb to distain 
los dientes wb,los$,q,x,c,n,t,c,s2,wb the teeth 
hasta wb,h,a,|,t,a.wb 
dest~r wb,dts I .t,lc,§,lr I ,wb 
wb,los3.l,a.g,o,s2,wb,d,¢,wb loslagos de 
los lagos a 
rancho 
wb,los3,I,a,g,o,s2,wb,a,wb 
wb,r,o,n,~,o,wb 
inmenso wb,lnl,m,c,n,s,o,wb 
wb,a,n,k,a,wb 
wb.o,a,n,g,a,wb ganga 
ajenjo 
nieto 
WbpilpN,t,fl,N~O,Wb 
wb,n,ldC,t,o,wb 
un hielo wb,un3,x,c,i,o,wb 
nuevo wb,n,u,c,v,o,wb 
un huevo wb,un3,u,c.v.o,wb 
UI'I OSO wb,un3,o,s,o,wb 
wb,kon l,p,a,d,r,c,wb  mr, e 
con padre wb,kon3,p,a,d,r,c,wb 
until 
to discolour 
the lakes of 
the lakes at 
ranch 
huge 
haunch 
bargain 
absinth 
grandson 
a frost 
new 
an e~8 
abear 
aquaintanee 
with father 
4.1.4 The Control Structure 
Optional boundaries are dealt with within 
the theory of LP by assuming that no 
boundary is specified in the rule and the rule 
is either attached to several strata (Halle and 
Mohanan, 1985) or to the first stratum 
following the resolution of all boundaries 
across which it may apply (Booij and 
Rubach, 1987). Following Booij and 
Rubach, I assumed that normal derivation up 
to word level would take place within a three 
stratum model consisting of cyclic, 
postcyclic and post lexical strata and 
therefore selected a five stratum model to 
begin the investigation (one for each level of 
affixation, plus one to ensure that rules 
could be applied after all word-formation 
processes were complete, including bracket 
erasure). The word formation processes 
were assigned in order with type 1 processes 
at stratum 1, type 2 at stratum 2, type 3 at 
stratum 3 and word boundaries at stratum 4. 
Five contrastive settings of the model, 
which varied only in the assignment of 
phonological rules to strata, were prepared: 
Table 6: The Hispanic Control settings 
Stratum C1 C2 c3 c4 c5 
1 10-16 10-16 10-16 10-16 10-16 
2 25-49 20-49 II-ll I1-11 II-II 
3 50-59 50-59 20-59 11-11 I1-11 
4 60-69 60-69 60-69 20-69 I1-11 
5 90-99 90-99 90-99 90-99 20-99 
Rule-sets allocated to strata may include 
"empty sets" if no rules have been allocated 
to any of the rule numbers assigned 
4.1.5 The Results 
Results are shown 
examples in Table 5. 
for each of the 
Table 7: Example Results (Hispanic study) 
r 
Cl C2/C3 
dcsdE dczd~ 
dzzdzfior 
C4 
Iosdzcntcs Iozdxznl¢s 
hasto 
dcstcflir 
Ioslagosdc 
Ioslagosa 
rondo 
xnmcnso imm~nso 
ank8 
genoa 
ON~OHO 
nx~lo 
Unlt|O 
DUEUO 
aQka 
gaQQe aacQXo 
unuzvo 
Inzlagosd¢ 
Iozla~ose 
Uf~W£VO 
C5 
Iozlagozdz 
unogo 
kompadr¢ 
konpadrc kompadr¢ 
The broad phonemic transcriptions 
resulting from the three data sets indicate a 
correspondence from the slow to fast speech 
with the re-assignment of the phonological 
rules from low to high strata. However, 
within this progression, the detailed analysis 
of the data presented by Harris demonstrates 
some anomalies. It is not possible to assign 
the settings CI-C5 to the speech styles 
Largo, Andante, Allegretto and Presto on a 
one-to-one (or even many-to-one) basis. At 
each level there may be forms which Harris 
assigns to contrasting styles. This may be 
partially due to the imperfect assignment of 
structure to the data items examined. 
For the Mexico City dialect, Largo speech 
roughly corresponds to settings C1-C2 of 
the LP control system proposed here for 
Spanish, Andante to C2-C3, Allegretto to 
C4-C5 and Presto may correspond to C5. 
Thus, the LP model, implemented in 
LexPhon, appears to give a reasonably good 
approximation to the data available. 
4.2. The English Study 
A more modest study of English style 
contrast data is included to examine whether 
similar stratum assignment of phonological 
rules can account for the casual/careful style 
contrasts found in standard British English. 
Again the Booij and Rubach model (1987) 
has been extended to investigate furlher 
aspects of the data through the inclusion of 
an additional stratum and the re-allocation of 
rules to strata. 
Descriptions of English style contrasts 
tend to be less well structured than the 
Harris (1969) study of the Mexico City 
dialect. The most common contrasts applied 
to spontaneous utterances are between 
careful and casual speech or between formal 
and informal speech. These two styles are 
sometimes, but not always, assumed to 
correspond. In either case, study is not 
limited to a comparison of binary 
alternations but usually relates to a series of 
utterance forms varying from one extreme of 
the style to the other. Laver (1991), for 
example, cites seven possible utterance 
forms for the single word 'actually' varying 
from most formal to most informal style in 
educated Southem British English. 
Kreidler (1989) lists vowel reduction, 
vowel loss, consonant loss and assimilation 
among the processes of reduction which 
contrast formal with informal or rapid 
English speech. Stress assignment is an 
important factor in identifying the contexts to 
which these apply and less formal speech 
may exhibit some or all of these processes. 
However, Kreidler suggests that apart from 
phonemic context, the familiarity of a 
particular word or phrase may also affect the 
amount of reduction which it may undergo. 
Although listing contrastive most careful and 
most casual forms, Kreidler too states that 
there may be one or more intermediate 
pronunciations. 
The Phonological Rules and Phoneme 
Inventory used here are the default databases 
provided for LexPhon, mainly derived from 
Halle and Mohanan's (1985) description of 
LP. Four strata were derived by adding an 
additional noncyclic stratum to the Booij and 
Rubach (1987) model and again 5 
contrastive settings were used in which 
blocks of the 24 ordered rules are 
progressively allocated to later strata to 
reflect more casual speech. The original 
rule-ordering is maintained throughout. 
Table 8: Control Settings for English Style 
Stratum C! C2 C3 C4 C5 
1 10-19 10-19 10-19 10-19 10-19 
2 30-79 30-40 20-20 20-20 20-20 
3 90-99 41-99 30-79 30-40 20-20 
4 99-99 99-99 90-99 41-99 30-99 ~ 
55 
Table 9: The English Data 
word(s) underlyin 8 form 
actually 
is it usual 
is she 
was she wb,w,o,z,wb,l,c,c,wb 
horse shoe wb,h,o,r,s ,wb, J,o,o,wb 
~naer ~hin wb.s.p.m.m.s.wb.J.l.p.wb space ship 
as yet 
this year 
not yet 
next year 
both you and 
me 
with you and 
u.gb,w,k,t,c,h ~11 ,lI I ,wb 
wb,l,z.wb,i,t,lUb,n,h,$,¢lnml I ,wb 
Wb,I,z,wb,LcOc,wb 
wb.m.z.wb.y.c.l.wb 
wb.6.1.s.wb.y.C.m.wb 
wb.n0o.t.wb.y.¢.t.wb 
wb.n.c.k.s.t.wb.y.c.m.tub 
wb.b.o.o.O.wb.y.o.o.wb.m.n.d.wb.m.c.t.wb 
W b,w,l,b,wb,y,o,o,wb,~,n,d,wb,m,l:,c,w b 
me 
nrohahlv wb,p,r,o,b,mbcl I j I ,wb probably 
supposed to 
don't know 
Wb.S.C.p.3.3.Z.d4.wb.t.o.O.Wb 
wb,d,o,o,wb,n,o,t,wb,n,o,u,wb 
I have to wb.l.l.wb.h.ee.v.wb.t.O.opwb 
she has to wb.J.c.c.wb.h.m.z.wb.t.o.o.wb 
Wb.w.l.l.wb.n.o0t .wb.y.o.o.wb won't you 
did you wb.dJ.d.wb.y.o.o.wb 
unless yOU wb.n.n.l.£.s.wb.y.o.o.IUb 
as you wb.ce.z.wb.y.o.o.wb 
what do y O U wb.w.m.t.wb.d.o.o.wb.y.o.o.wb.n.c.¢.d.wb 
need 
what does it wb.w.m.t.wb.d.o.o.s4.wb.t.t.wb.m.lo.t.c.wb 
matter 
what did John wb.w.m.t.wb.d.Ld.wb.~.o.n.wb.s.m.m.wb 
say 
Table 10: The English Results 
C1/C2/C3 C4 C5 
~ekl~ouaelz 
IZltuu3uu~l IZI~UU3UU~BI 
WOZJII 
harsJuu 
spc,slzP 
mzyct m3cl 
6xlcm 615~E~ 
notyct 
nckstQcm 
bouOyuumndmlI 
wz6~uumndmzz 
probeebclx 
scpouzdtuu 
duunotnou 
mlh~utuu 
Jzzhmztuu 
wzlnot~luu 
dzdyuu 
¢~nles~uu 
aezyuu 
waetdUU~lUUnZzd 
wmtduusztmmtE 
wmtdxd~onscz 
nolJct 
ncks~cm 
bouJuuaondml! 
wz~uumndmH 
wxlnol~uu 
dxCzuu 
nnlcluu 
~3uu 
noltt 
wxlnoJuu 
dx3uu 
The first setting is the default setting for 
LexPhon and no distinction was found 
between this and the results of next two 
settings in which some or all of the 
noncyclic rules from stratum 2 were shifted 
56 
to stratum 3. Word-internal assimilations 
involving y-insertion and palatalization have 
taken place. At the fourth setting, in which 
many of the noncyclic rules are attached to 
the final stratum and are applied after all 
word-formation is complete, a number of 
assimilations involving palatalization and y- 
insertion take place across word boundaries 
as well as word-internally. 
Further variations are demonstrated 
between the fourth and fifth settings. At the 
fifth setting all post-cyclic rules operate 
within the final, post-word-level, stratum 
causing spimntization to apply to contexts 
spanning word-boundaries. 
The variations resulting from the first 
three settings generally reflect a relatively 
formal, carefully pronounced speech style, 
although certain reductions characteristic of 
spoken rather than written English have not 
taken place (e.g. 'will not' rather than 
'won't'). Some reductions found at the 
fourth setting in such partial clauses as 
'unless you' and 'did you' are attested by 
Kreidler (1989) as casual speech forms. 
However, I have found no evidence in the 
literature for other reductions found at the 
fourth setting, nor for the further fricative 
reductions found at the fifth setting. These 
latter appear to be more typical of "slurred" 
speech than casual speech. 
Much of the style-related variation 
reported by Laver and Kreidler does not 
occur as a result of the LexPhon settings 
tested above. However, the variations 
which they reported are characterised by 
phonological rules such as fricative 
assimilation (Kreidler, p257) and cluster 
reductions, not required (or not yet 
implemented in LexPhon) for the derivation 
of the standard forms of the utterances. 
Thus, the model provides a partial but 
inadequate description of careful/casual 
contrasts found in British English. 
5. SUMMARY AND CONCLUSIONS 
LexPhon, a computational framework 
for models of lexical phonology, has been 
described and an example application of one 
potential use of such a system has been 
presented. 
Using LexPhon, contrastive L P 
structures were applied to Spanish and 
English data in the context of language- 
dependant Phoneme Inventories and 
Phonological Rule sets. 
A hypothesis was tested that intm-speaker 
style variation might be the result of 
applying the same rules to the same 
underlying forms but at different stages of 
the utterance formation process. In the case 
of the Spanish data for the Mexico City 
dialect, allocation of rules to strata appears to 
account for a substantial proportion of the 
attested variation between the speech speed 
styles. For the contrastive study of English 
careful versus ~tsual style data, re-allocation 
of rules to strata appears to account for a 
smaller proportion of the variation attested, 
in spite of the use of a much more 
comprehensive rule set. 
Although the studies presented here are 
not conclusivei they provide evidence which 
gives support to the theory that aspects of 
style variation may be attributable to the level 
of word-formation at which phonological 
rules are applied, rather than necessarily to 
differences in the formulation of the rules 
themselves. This supports the LP 
hypothesis that complex surface phonology 
of languages may be the result of 
interactions between relatively simple 
morphological and phonological processes 
taking place within a simple framework. 
Further, the application of LexPhon to a 
problem requiring alternative phoneme 
inventory, phonological rulebase and LP 
control framework demonstrates the 
flexibility which the system can offer to 
comparative studies in lexical phonology. 

REFERENCES 
Booij, G,; Rubach, J. i 987 Postcyclic v. Postlexical 
Rules in Lexical Phonology, Linguistic Inquiry 
18(1). 
Chomsky, N.; Halle, M, 1968 Sound Pattern of 
English. Harper & Row. 
Halle, M.; Moltanan, K. P. 1985 Segmental 
Phonology of Modem English. Linguistic Inquiry 
16(1), 57-116. 
Halle, M.; Vernaud, J.-R. 1982 On the Framework 
of Autosegmental Phonology. The Structure of 
Phonological Representations (Part 1). eds. van der 
Hulst, H,, Smith, N., Foris. 
Harris, J. W. 1969 Spanish Phonology. Cambridge 
Massachusetts: MIT Press. 
van der Hulst, H,; Smith N. 1982 An Overview of 
Autosegmentai and Metrical Phonology. The 
Structure of Phonological Representations (Part I). 
eds. van der Hulst, H,, Smith, N., Foris. 
Kiparsky, P, 1982 From Cyclic Phonology to 
Lexicai Phonology, 772e Structure of Phonological 
Representations (Part I). eds. van der Hulst, H., Smith, N,, Foals. 
K~parsky, P. 1982b Lexical Morphology and 
Phonology. Linguistics in the Morning Calm: 
Selected Papers from SICOL-1981. edited by the 
iLinguistic Society of Korea, Hanshin Publishing 
!Company: Seoul, Korea. 
eidler, C. W. 1989 of English. K~ford: The Pronunciation 
Blackwell. 
Labov, W. 1981 Field methods used by the project 
\[on linguistic change and variation. Sociolinguistic 
iworking paper 81, Austin Texas: South Western 
~Education Development Laboratory. 
I.~ver, J. 1991 The Gitt of Speech. Edinburgh 
University Press. 
Leben, W. 1982 Metrical or Autosegmental. The 
\[Structure of Phonological Representations (Part I). 
eds. van der Hulst, H., Smith, N., Foils. 
L\[isterri, J. 1992 Speaking styles in speech research. 
Proc. ELSNET/ESCA/SALT Workshop on 
llntegrating Speech and Natural Language, Dublin, 
ilreland. 
Mllroy, L. 1987 Observing and Analysing Natural 
:Language. Oxford: Basil Blackwell. 
T~anel, B. 1987 French schwa and nonlinear 
hOnology. Linguistics 25(1 ), 845-866. 
liams, S. M. 1993 LexPhon: A computational 
plementation of lexical phonology. PhD 
esis, University of Reading, UK. 
