Compositional Semantics of German Prefix Verbs 
Maria Wolters 
Institut fiir Kommunikationsforschung und Phonetik 
University of Bonn 
Poppelsdorfer Allee 47, D-53115 Bonn 
mwo©asll, ikp. uni-bonn, de 
Abstract 
A compositional account of the semantics 
of German prefix verbs in HPSG is out- 
lined. We consider only those verbs that 
are formed by productive synchronic rules. 
Rules are fully productive if they apply to 
all base verbs which satisfy a common de- 
scription. Prefixes can be polysemous and 
have separate, highly underspecified lexical 
entries. Adequate bases are determined via 
selection restrictions. 
1 The Problem 
Determining the semantics of unknown words which 
can be derived from lexicon entries is highly de- 
sirable for natural language understanding (Light, 
1996). In this paper, I sketch a compositional ac- 
count of the semantics of German prefix verbs de- 
rived from a verbal base, concentrating on those 
verbs that can be generated by a productive word 
formation rule. Like (Witte, 1997), I assume that 
the meaning of most of these verbs can be derived 
compositionally by uni~'ing the semantic represen- 
tations of its constituents. Example: 
(1) durch + laufen ('through + to run') =~ 
durchlaufen ('to run through') 
This is an instance of a common rule which can be 
summarized informally ms 
(2) 'durch' + VERB\[+motion,+agentive\] ::~ 
VERB through a space 
When a prefix verb is lexicalized, its meaning fre- 
quently shifts due to language change and metaphor- 
ical usage (Mayo et al., 1995). For example, 'durch- 
laufen' is mostly associated with the meaning "pass- 
ing through all stages of a process": 
(3) Er durchl£uft die Schulung. 
He passes through the training. 
2 The Semantics of Prefix Verbs 
Frequently, the prefix modifies features of the base 
verb such as valency or aspect 1. For example, while 
'eilen' ('to haste') is an activity, 'etw. dureheilen' 
('to haste through sth.') is an accomplishment. I 
assume that the prefix entry provides a highly un- 
derspecified blueprint of the structure of the prefix 
verb; therefore, I regard the prefix as the head of the 
prefix verb (but see (Bauer, 1990)). 
The values for all features of the prefix verb are 
obtained from the base verb via structure sharing, 
except for basic morphological information and the 
information to be modified. In other words, the val- 
ues of all unmodified features of the prefix verb are 
token identical with the corresponding values of the 
base verb. 
Most prefixes appear in distinct but semantically 
related rules, resulting in polysemou,s prefixes. For 
example, combined with some stative verbs, 'durch' 
signifies "'VERB during a certain period of time", as 
in 
(4) durch + leben ('through' + 'live') =~ 
durchleben ('live through:) 
Specifying the set of adequate bases implicitly by 
selection restrictions allows to elegantly capture gen- 
eralizations. For example, we can specify at the 
feature structure for verbs of motion that they can 
only combine with the instance of "durch' denoting 
"VERB through a space". 
The productivity of a word formation rule is 
a complex notion (Kastovsky, 1986; Bauer, 1988; 
Mayo et al., 1995). For our purposes, a rule is pro- 
ductive if it applies to all bases which satisfy a com- 
mon description such as "'state" or "transitive verb". 
A rule only provides patterns for analogical forma- 
1Here. aspect denotes certain general verb classes 
(Binnick. 1992; Comrie. 1992) such as state, activity, 
accomplishment, and achievement (Vendler, 1957). 
525 
tions; the frequency of application and acceptability 
of results also indicate its degree of productivity. 
3 Prefix Semantics in HPSG 
The main advantage of HPSG (Head Driven Phrase 
Structure Grammar, (Pollard and Sag, 1994), for 
German see e.g.(Kathol, 1995)) is that it is both a 
formalism with strong ties to logic and knowledge 
representation and a linguistic theory. Much re- 
search in HPSG focuses on the structure of the lexi- 
con, e.g. (Davis, 1997). However, work on semantics 
and morphology in HPSG is relatively scarce. 
3.1 Previous Work 
lVlost HPSG work on German affixation focuses on 
the suffix -bar, which can combine with verbs, most 
of them transitive, to form an adjective. 
(Krieger and Nerbonne, 1992) (KN) assign sepa- 
rate lexical entries to affixes and express selection 
restrictions by typing and subcategorization frames. 
In their model, -bar is of sort bar-surf and subcate- 
gorizes for verbs of sort bar-verb to form adjectives 
of sort bar-comp-adj. Complex words have a headed 
binary structure, with the affix as head. In keeping 
with the I-IPSG Semant, ics Principle, the semantics 
of the complex word is structure shared with the 
semantics of the head. 
(Riehemann, 1993) found that subcategorization 
frames were incompatible with her data. Instead 
of a word syntactic approach with separate lexical 
entries for affixes, she describes the formation of bar- 
adjectives via a lexical inheritance hierarchy of sorts. 
Different sorts correspond to different types of verbal 
bases (transitive, dative, etc.). New adjectives are 
formed in analogy to existing ones. 
Although Riehemann's approach is very elegant, 
it is not adequate for verb prefixes. Most prefixes 
can be separated from the verb depending on their 
phonological level, e Example: 
(5) Ich mache die Tiir zu. ('I close the door'; 
zumachen = 'to close') 
Therefore, a word syntactic approach and separate 
lexicM entries for verb prefixes may well be adequate. 
(Witte, 1997) also advocates a word syntactic ap- 
proach. His semantic representation relies on (Davis, 
1997). (Light, 1996) bases his semantic representa- 
tions on first order logic, but he does not use HPSG. 
3.2 Verb Prefixes 
Fig. 1 presents the prefix-related part of the sort 
hierarchy. The sort verb-prefix specifies typical lea- 
2 Le.,dcM Phonology (Mohanan, 1987) assumes several 
levels of rules. 
verb-prefix 
durch 
durch_l dutch2 
Figure 1: Part of the sort hierarchy for verb prefixes 
tures of verb prefixes. Each prefix p is assigned a sort 
p with subsorts Pl ..... Pn for each potential mean- 
ing. Relevant verb classes, such as semantic fields or 
Vendler classes, are also specified using sorts. 
Following KN, I assume that the prefix is the head 
of complex affix words, but like Riehemann, I do not 
assume a binary structure. The internal structure of 
a complex derived word is given in Fig. 2. Morpho- 
logical information is given at the feature MORPII. 
MORPtIILEVEL specifies separability (1 - unsepara- 
ble, 2 - separable). MORPHIDTRS the internal struc- 
ture, and MORPHIB.-kSE the base form. 
Each verb has a complex feature PREFIX located 
at SYNSEMILOCICAT. FOr each prefix p, the value 
of the subfeature PREFIXIp points to the adequate 
prefix meaning. For example, if the instance of 
'dutch' corresponding to (2) is labelled dutch_l, we 
get PREFIX\]DURCtI: 1 in the lexical entry for 'eilen'. 
A verb can only combine with prefixes for which 
an instance is specified at PREFIX. Regarding se- 
mantics, we focus on aspectual classes. The se- 
mantic framework chosen here is Lexical Concep- 
tual Structure, which has been applied successfidly 
to the interface between morphology and lexical se- 
mantics by e.g. (Rappaport Hovav and Levin, in 
press). The representation of "v~ndler classes is 
adapted from (Van Valin, 1990). Class is specified 
at SYNSEMII, OClCONTENTICr, Ass. 
Prefix entries are heavily underspecified. For ex- 
ample, the entry for "durch' can be derived from 
Fig. 2 by deleting all information specific to 
the COMPlement "eilen'. except for the value of 
PREFIX\]DIRCII. The semantics of the complex word 
is composed at the head and then structure shared 
with the whole word, in accordance with the Seman- 
tics Principle. A prefix can only be combined with 
verbs with an adequate feature value at PREFIX. 
4 Conclusion and Further Work 
The representation of the relevant semantics will for- 
realized more rigorously. Hypotheses will be checked 
with the data, using a more refined, statistically mo- 
tivated notion of productivity. The theory will also 
be implemented in an adequate lexical knowledge 
526 
MORPH 
'BASE cond_concat(V~, \[\]) 
SYNSEM\[\] r,OCICONTJCLASS CAUSE \[\] 
L,~,A,,s~ BECOME(\['3\], XOT IN r~) 
DTRS 
"MORPHIBASE \[\] 'ellen' 
( \[c Assloo \[\] COMPS 
SYNSEMILOC CONT /NUC \[\] \[RELN eilen \] 
L \[AGENT \[\] NP\] 
F, YNSEM \[\] 
Figure 2: Partial lexical entry for 'durcheilen'. 4 refers to the direct object. 3 to the subject 
representation language. 
Acknowledgements 
Thanks to Bernhard SchrSder and three anonymous 
reviewers for their valuable comments. This research 
was partially supported by the Studienstiftung des 
deutschen Volkes and ERASMUS. 

References 
L. Bauer. 1988. Introducing Linguistic Morphology. 
Edinburgh University Press, Edinburgh. 
L. Bauer. 1990. Be-heading the word. J. Linguis- 
tics, 26:1-31. 
R. Binnick. 1992. Time and the Verb. Oxford Uni- 
versity Press, Oxford. 
B. Comrie. 1992. Aspect. Cambridge University 
Press, Cambridge. 
A. Davis. 1997. Lexical Semantics and Linking and 
the Hierarchical Lexicon. Ph.D. thesis, Depart- 
ment of Linguistics, Stanford University. 
D. Kastovsky. 1986. The problem of productivity in 
word-formation. Linguistics, 24:585-600. 
A. Kathol. 1995. Linearization-Based German Syn- 
tax. Ph.D. thesis, Department of Linguistics, 
Stanford University. 
H.-U. Krieger and J. Nerbonne. 1992. Feature-ba~sed 
inheritance networks for computational lexicons. 
In Ted Briscoe, Valeria de Paiva, and Ann Copes- 
take, editors, Inheritance, Defaults and the Lexi- 
con, chapter 7, pages 90-136. Cambridge Univer- 
sity Press. 
M. Light. 1996. Morphological Cues for Lexieal Se- 
mantics. Ph.D. thesis, Department of Computer 
Science, University of Rochester. 
B. Mayo, M.-T. Schepping, C. Schwarze, and A. Zal- 
fanella. 1995. Semantics in the derivational mor- 
phology of Italian: implications for the structure 
of the lexicon. Linguistics, 33:583-638. 
K.P. Mohanan. 1987. The Theory of Lexieal Phonol- 
ogy. Reidel, Dordrecht. 
C. Pollard and I. Sag. 1994. Head-Driven Phrase 
Structure Gramraar. University of Chicago Press. 
M. Rappaport Hovav and B. Levin. in press. Mor- 
phology and lexical semantics. In A. Zwicky 
and A. Spencer. editors. Handbook of Morphology. 
Blackwell, Oxford. 
S. Riehemann. 1993. Word formation in lexical type 
hierarchies - a case study of bar-adjectives in Ger- 
man. Master's thesis, Universit£t Tiibingen. SfS- 
Report-02-93. 
R.D. Van VMin. 1990. Semantic parameters of split 
intransitivity. Language. 66:221-260. 
Z. ~ndler. 1957. Verbs and times. Philosophical 
Review, 56:143-160. 
J. Witte. 1997. CompositionM semantics for resul- 
tative separable prefix constructions in German. 
In Proe. HPSG 4. 
