Inquiry Semantics: 
A Functional Semantics of Natural Language Grammar 1 
William C. Mann 
USC/Information Sciences Institute 
4676 Admiralty Way 
Marina del Rey, California 90292 
USA 
Summary 
Programming a computer to operate to a significant 
degree as an author is a challenging research task. The 
creation of fluent multiparagraph text is a complex 
process because knowledge must be expressed in 
linguistic forms at several levels of organization, 
including paragraphs, sentences and words, each of 
which involves its own kinds of complexity. 
Accommodating this natural complexity is a difficult 
design problem. To solve it we must separate the 
various relevant kinds of knowledge into nearly 
independent collections, factoring the problem. 
Inquiry semantics is a new factoring of the text 
generation problem. It is novel in that it provides a 
distinct semantics for the grammar, independent of 
world knowledge, discourse knowledge, text plans and 
the lexicon, but appropriately linked to each. It has 
been implemented as part of the Nigel text generation 
grammar of English. 
This paper characterizes inquiry semantics, shows 
how it factors text generation, and describes its 
exemplification in NigeL The resulting description of 
inquiries for English has three dimensions: the 
varieties of operations on information, the varieties of 
information operated upon, and the subject matter of 
the operations. The definition framework for inquiries 
involves both traditional and nontraditional linguistic 
abstractions, spanning the knowledge to be 
represented and the plans required for presenting it. 
1 Introduction 
Text generation is the generation of language to 
conform to an a priori intention and plan to communicate. 
The problem of text generation is naturally complex, requiring the 
1previous title: Generating Text: Knowledge a Grammar Demands. 
This research was SUl~ported by the Air Force Office of Scientific Research 
contract No, F49620-79-C-0181. The views and conclusions contained in this 
document are those of the author and should not be interpreted as necessarily 
representing the official policies or endorsements, either expressed or implied, of 
Ihe Air Force Office of Scientific Research of the U.S Government. 
active coordination of many kinds of knowledge having 
independent origins and character. A significant part of this 
complexity is in grammatical knowledge. It is important for the 
grammar of a text generator to have its own integrity, yet without 
being operationally autonomous. 2 
The methods of generating text presented here grew out of 
a concern to maintain the integrity and definitional independence 
of particular existing fragments of grammar. These methods 
employ the grammar in ways which do not make any strong 
assumptions about the nongrammatical kinds of knowledge in the 
text generator. They control the use of the grammar in 
generation. 
We-first describe the methods, showing how they make 
grammatical generation possible. Then we show how they factor 
the problem of text generation and clarify the role of knowledge 
representations. Finally we characterize inquiry semantics and 
the notion of meaning. 
2 Grammar and Control 
People often anticipate that a text generator will plan the 
operations of the grammar in full detail and then execute such 
plans. In fact, such a mode of operation has serious difficulties, 
and so it is worthwhile to consider other approaches. Even given 
the definition of a grammar and a particular way of manipulating it 
to produce text, there is an issue of where the initiative should be 
exercised in generation. Should the responsibility for conformity 
of ',he result to the given intention and plan lie within Ihe grammar 
manipulator, i.e., be part of its process of employing the grammar, 
or are the details of grammar use preplanned? It is an issue of 
control. 
2This role of intention in the use of language is one of the reasons for calling the 
semantics in this paper a functional semantics Another is our uSe of one of the 
"functional" linguistic traditions 
165 
To see the problem more clearly we can compare 
controlling the grammar to steering a car. 
If we intend to drive to a nearby store, we can 
imagine planning the trip (in terms of steering motions) 
in total detail, deciding just where to turn, change 
lanes, and so forth, with sufficient precision to insure 
success. This detailed plan could in principle then be 
used to steer the car to the store. Such methods of 
imposed control are practical only in very simple 
cases. 
Alternatively, we can make the decisions about 
steering at the point of need, on demand. 
Unanticipated conditions are thus allowed for, and the 
complexity of the task is reduced. (There is no need to 
compensate in the plan for tire pressures, for example.) 
At each significant point along the way, the driver 
chooses a direction that conforms to the goal of 
reaching the destination. This is an active 
conformity approach, in which decisions about 
direction are made while the trip is in progress. 
With imposed control, information about how to satisfy the 
intention and plan is needed before the process is started. With 
active conformity, information is needed as the process proceeds. 
The design of our generation methods is based on active 
conformity. The grammar demands the information it needs about 
the plan as generation proceeds. 
What does a purposefully generating grammar need to 
know? As part of the development of the Penman text-generation 
;,,~gr~m, we have created a large systemic grammar of Englis h 
iMann 83\]. Penman is designed to create a text plan and then 
execute it by giving it, one sentential element at a time, to the 
grRmmar. The grammar, which is called Nigel, operates on its own 
initiative, requesting information about the planned text as it is 
needed. The central organizing concept in the grammar is 
choice. The language offers a variety of grammatical options that 
:?,~ !~ represented as sets of alternatives, and means for 
producing surface forms from particular combinations of choices 
made among the alternatives. All syntactic options are expressed 
in the sets of alternatives. In any one set, choosing one option 
excludes all of the others. Nigel contains over 200 systems 
(collections of alternatives in systemic notation), along with 
provisions for realizing choices as structures, an experimental 
lexicon used to give the structures surface forms, and extensive 
provisions for experimental control. 3 
Given this orientation toward choice, the problem of 
conformity to the text plan is simply the problem of making 
appropriate choices. Each set of alternatives (each "system" in 
its systemic representation has an associated chooser or 
choice expert, a process that embodies a method for choosing 
appropriately in any particular circumstance. 
The choice experts require certain information as they 
proceed with text generation. Nigei's choice experts request this 
information by presenting inquiries to the environment (the 
place outside of the grammar where intentions and plans to 
communicate are found.) For this purpose, Nigel employs a 
formal inquiry language in which an inquiry is an expression 
containing an inquiry operator and a sequence of operands. A 
single interface is provided for all interactions between Nigel and 
the environment; all interactions at the interface are in the inquiry 
language. This way of using such an interface is called inquiry 
semantics. 
In this framework, we can understand the demands of the 
grammar by understanding the inquiry operators. 
3 Varieties of Demands 
This section characterizes the demands for information 
that Nigel can make in generating sentences. Since Nigel 
demands information only by presenting inquiries, we first " 
characterize the things that Nigel can inquire about (the operands 
of inquiries), then characterize in two different ways the questions 
that Nigel can ask. 
3.1 Categories of Operands of Inquiries 
Nigel has four related information forms: 
1. Concept symbols 
2. Presentation specifications 
3. Term sets 
4. Terms 
Concept symbols are names assigned by the 
environment to particular elements of its knowledge, either in the 
text plan for the text being formed or in the environment's 
knowledge base. A concept symbol represents an entity that may 
be simple or complex, decomposable or not; the symbols 
3The grammar is written in an extended systemic notation and draws extensively 
on precedents in the work of Halliday and others \[Berry 75, Berry 77. Halliday & 
Hasan 76, Halliday 76, Hudson 76, Halliday & Martin 81,de Joia & $tenton 
80. Fawcett 80\]. We gratefully acknowledge the participation of Michael Halliday 
and Christian Matthiessen in the work. 
166 
themselves are not decomposable. A concept symbol does not 
have to bear any particular relationship to any kind of linguistic 
entity. 
Presentation specifications are formal descriptions of 
the information that should be expressed in a particular reference, 
description, or predication. Through presentation specifications 
the environment designates the content to be conveyed in each 
~rt.icular constituent, (but not how the content is to be 
expressed.) 
For nominal groups (NP's). for example, presentation 
specifications represent the identification of the content to 
present about the particular object, process, or relation which the 
nominal group represents. The collection of devices that express 
nominal group content include head terms (nouns, pronouns, 
substitute "one"), modifying nominals, adjectives and adjective 
groups, quantifiers, numerals, determiners, prepositional phrases, 
restrictive and nonrestrictive relative clauses. Normally the 
grammar will use some combination of these devices in the 
nominal group to express all of the content of the presentation 
specification. 
As a minimal example, the grammar's decision on whether 
a pronoun is adequate as a referring phrase can be made on the 
basis of the presentation specification, since the specification tells 
what constitutes adequate reference at the point of referring. (If 
the presentation specification indicates that nothing beyond 
gender and number needs to be expressed, a pronoun is used.) 
The presentation specification is thus a unifying device for 
all of the conceptual elements of an intention to refer. It is 
essential to the generation task because the various syntactic 
devices effectively compete for the content which the nominal 
group expresses in referring. 
At the clause level, presentation specifications operate 
comparably, unifying the effects of adverbial, conjunctive, and 
clausal modifiers. The specifications are constructed units, not 
frames or delimited regions of knowledge. 
Term sets are collections of lexical items created in a 
special way which insures that they are appropriate, in denotation, 
:cmnotation, and information content, for their intended use. (The 
,~;=cess which creates term sets does not restrict them 
syntactically; that is done later by the grammar.) The individual 
terms in a term set need not be so restrictive that they fully express 
the intent of the unit being constructed, since they are used with 
modifiers. Term sets are not like sets of synonyms since they do 
not have any uniformity of semantic content. 
Term sets are used as collections of alternatives, from 
which one term will be picked for the final syntactic unit. The best 
example is a term set giving alternatives that can serve as the 
head term of a nominal group. 
A Term is a single lexical item selected from a term set. It 
identifies the particular lexical item to appear in the generated 
text. Currently Nigel is deliberately underdeveloped in its 
treatment of lexical items, having no morphological component at 
all. Hence terms are simply lexical items which bear lexical 
features that the grammar can employ for selectivity. 
To see how these forms are used, consider the sentence: 
The leader is John. 
It refers to John twice. In generating this sentence, the 
same concept symbol, say JLDR, would be used to generate both 
;f the references. However, two different presentation 
specifications for referring to JLDR would be created. The first 
might specify that the resulting expression should convey the fact 
that the individual holds the role of leader. The second could 
merely specify that the resulting expression should convey the 
person's name. 
Two different term sets would also be created. Initially, 
each would contain conceptually and denotationally appropriate 
terms, possibly including "leader," "man," and "person," in one 
cf *.he term sets, and "John," and "Mr. Jones" in the other. Under 
guidance from various inquiries, the grammar applies different 
selectivity to one term set than to the other, so that the terms 
"leader" and "John" are finally selected. 
How do these operands of inquiries compare with 
conventional linguistic abstractions? 
Concept symbols have many precedents, and terms are 
familiar. Both presentation specifications and term sets are new. 
As we will see, both presentation specifications and term sets are 
widely and frequently used in the grammar. Their central role in 
generation suggests that they are worthy of linguistic attention. 
167 
Presentation specifications are novel in that they represent 
the content of particular units without its allocation to constituent 
units. This permits the investigation of how the allocation works, 
and in particular how differing ranks compete for representational 
roles. Competition among the possible consitiuents of a nominal 
group for representation of posession seems to be a typical case. 
We would like to know, for example how the decision between 
using the determiner "his," the prepositional phrase "of his," and 
the clause "which he has" is made. A presentation specification 
can say in a syntactically neutral way that possession is to be 
expressed. Using them facilitates study of the alternation. 
Nigel uses subtractive operations on presentation 
specifications to account for the fact that repeated expression of 
content in a nominal group is marked, but single expression is not. 
~.,, it can account for the perception that "his car. which he owns" 
is marked in a way in which "his car, which he hates" is not. 
Term sets are novel in that they represent the alternations 
and :ompetition among lexical items. The sets of terms which 
compete as candidates, e.g. for the main verb of a clause or head 
term of a nominal group, are highly variable and dependent on the 
~'.ubj~ct matter of the communication. Hence they are not 
susceptible to static analysis as part of the grammar, and they are 
not easy to represent in systemic systems. 
Consider, for example, the word "attention" at the end of 
the third paragraph back. Other candidates for use in the same 
setting would include words such as "research." "curiosity," 
"work." "perusal." and "funds." These terms (as well as 
"attention") would all be in the term set for generating that 
nominal group. However, they are from different lexical fields, 
fields which are ordinarily not in alternation. Since they are not 
the basis of a stable alternation, many sorts of static 
representations of them (including representation in systems in a 
systemic lexico-grammar) seem inappropriate. The situation is 
much more complex and dynamic, worthy of linguistic attention. 
Notice that in both cases, addition of a new formal 
c3:~struct will facilitate study of how particular expressions are 
related to closely related alternatives in ways which are not in 
~.~po3ition in a conventional systemic account. Studies of 
functional alternation have long been a highly valued activity 
among systemicists. 
Notice also that these constructs arise easily, almost 
;nevitably, in studies of text construction, but are not inevitable at 
all in descriotive studies of text. Given a particular text to study, it 
=s not at all clear what the rejected head term candidates were, nor 
what the alternate allocations of content to syntactic units might 
have been. In systemic terms, part of the meaning of a nominal 
g,ouo is derived from the particular choice of the head term. but, 
working descriptively, the alternation is hard to characterize. 
Study of text generation (and related work on constructive 
characterization) thus complements other methodologies in that it 
n, ~.=.s certain difficult tasks easier. 
3.2 Abstract Categories of Inquiry Operators 
The inquiries of the grammar can be differentiated 
according to categories of purposes they serve. Five such 
categories are described below. The first two kinds of inquiries 
~ ~ :.'~-ed for control, and the last three extract symbols from the 
environment -- either lexical items or symbols that can be included 
as subject matter in subsequent inquiries. Inquiries of the first two 
kinds have predetermined closed sets of possible responses: the 
last three kinds allow an unlimited number of responses. 
1. information availability 
2. information characterization 
3. decomposition 
4, linking (identification of related information) 
5. mapping 
Some inquiries determine whether information of a certain 
character is available, such as the location or duration of an 
event. These inquiries generally precede others used to 
characterize information. 
The operators used for information characterization 
form the largest collection of operators among the five kinds. 
They are used to subcategorize and also to discover relations of 
inclusion, identity, precedence, adjacency, and attributes of 
manner, number, completeness, intended emphasis, identifiability 
to the reader, decomposability, gender, hypotheticality, 
extensionality, and many other sorts. 
When the grammar has determined that some of the 
available informaion is decomposable into parts in a syntactically 
significant way (usually through information availability inquiries), 
information decomposition inquiries are used to obtain access 
168 
to the parts. This is the largest category of inquiries for which an 
unlimited diversity of responses is allowed. These inquiries offer 
access to actors, affected objects, processes, causers, polarities, 
locations, time periods, extents, manners, and various kinds of 
participants or conditioners of processes. 
The linking inquiries are a small collection of inquiries 
which resemble the information decomposition inquiries. They 
obtain information related in a particular way to known 
information, but not part of it. For example, given an event whose 
time must be expressed, there is an inquiry that obtains the 
identity of the time relative to which the event's time of occurrence 
should be expressed. 
In terms of the four forms of information presented in 
section 3.1 above, exploration always proceeds from concepts to 
presentation specifications and term sets, and from term sets to 
terms, as shown in Figure 1. 
Concepts ,/-..., 
Presentation Specifications Term Sets 
Terms 
Figure 1: Information flow through mapping inquiries 
A small collection of Mapping inquiries participate in this 
:~,ploration at the points where information forms change. 
Several create specialized presentation specifications for 
concepts, and others create term sets and terms. 
Since operators can request presentation specifications, 
they can in effect demand that the environment work out what 
information to include in a new reference to an entity. The 
e,~vironment must then use the knowledge of past mentions, a 
model of the hearer's attention and of possible confusion 
candidates, and also the knowledge of denotationally appropriate 
le.<ic.~l items; these elements of knowledge are all outside the 
ooundary of the grammar. The mapping from concepts to 
presentation specifications is thus dependent on the particular 
circumstances. 
In a similar way, the mappings from concepts to term sets 
and from term sets to terms also vary depending on the 
comm,mication situation. 
3.3 Categories of Subject Matter 
Recurrent topics and categories of subject matter in the 
inquiries reflect the syntactically encoded categories Of 
knowledge in English. The subject matter categories form two 
groups: 
1. Elements of knowledge that typically exist odor to the 
intention or plan to communicate (described in 
section 3.3.1 below), and 
2. Elements of knowledge ~:r~ated as Dad of pursuing 
the intention or plan to communicate (described in 
section 3.3.2 below.) 
These are called the Knowledge Base and the Text 
Plan, respectively. 
Surprisingly, we do not see any sharing of inquiries 
between these two kinds of knowledge. In Nigel, we find that each 
inquiry operator addresses solely one body of knowledge or the 
other. A few of the categories of operations address both kinds of 
knowledge, notably inquiries about availability of information. 
Within the categories, however, each individual inquiry is 
specialized to a single kind of knowledge. 
3.3.1 Subject Matter of Inquiries Concerning Prior 
Knowledge 
In addition to inquiring about availability of information, the 
grammar asks about abstract characteristics of processes, about 
number and discreteness, and about time and space. Also, there 
is ~ substantial collection of inquiries about logical relations such 
as set membership, interval inclusion, identity of two entities, 
extensionality, definiteness of existence, hypotheticality, polarity 
and conditionality. 
3.3.2 Subject Matter of Inquiries for Communication 
Among the inquiry operators that refer to information 
created in pursuit of an intention or plan to communicate, there 
are inquiries about speech acts and about controlling the hearer's 
attention. The latter are used in controlling thematicity, various 
kinds of marking, and the foregrounding or backgrounding of 
information. 
3.4 Support Processes in the Environment 
The organization of inquiry requires that various kinds of 
processes be available in the environment for responding to 
inquiries. At a detailed level, there must be a capability for the 
169 
environment to recognize each inquiry operator and to respond to 
each one appropriately. In computational terms, for a particular 
domain of expressive problems, all of the inquiry operators which 
are called upon to serve that domain must be implemented. (For 
simple expressive problems this can be far fewer than the total for 
the grammar.) 
At a more comprehensive level, we can identify certain 
recurrent activities which must underlie the operations of the 
inquiry operator implementations. These include searching for an 
appropriate set of.lexical items (such as candidate head nouns for 
a nominal group), creating a presentation specification for 
expressing a particular idea, and choosing among a set of terms 
which the grammar has approved as appropriate for a certain use. 
At an even more comprehensive level, the grammar relies 
or; the prior activity of processes which plan the text. 
a, Inquiries in Action: An example 
The following list summarizes Nigel's activity in developing 
a particular nominal group: "her appointment on Wednesday 
morning with us." The starting point is identification of a need to 
refer to an object represented by concept APPOINTMENT. At the 
end of the activity shown, there is a structure containing the word 
"appointment" as the head term, the word "her" as its determiner, 
and elements that could be further developed into the phrases "on 
Wednesday morning" and "with us." The category of each 
inquiry operator is indicated in <brackets>. The order of 
presentation is the order actually used in the program. It is 
somewhat disconnected, since the program often Chooses in an 
arbitrary way between several things which it could do next. An 
inquiry appears more than once if it is used by more than one 
choice expert. 
1. Obtain a presentation specification for 
APPOINTMENT <mapping> 
developing the head term of the group 
2. Obtain a set of candidate head terms <mapping> 
3. Establish that APPOINTMENT is countable 
<characterization> 
4. Classify APPOINTMENT as 
<characterization> 
5. Classify APPOINTMENT as unitary <characterization> 
extensional 
6. Classify APPOINTMENT as not a question variable 
<characterization> 
7. Classify APPOINTMENT as extensional (as part of 
pronoun control) <characterization> 
8. Classify APPOINTMENT as unitary (as part of pronoun 
control) <characterization> 
9. Establish that the gender of APPOINTMENT is known 
<availability> 
10. Establish that in the presentation specification of 
APPOINTMENT, there is more to be expressed than 
gender and number <characterization> 
11. Determine that it is preferab!e to exclude proper 
nouns from the term set, rather than exclude the 
remainder <preference> 
begin developing the determiner 
12. Establish that APPOINTMENT is extensional (for 
determiner control) <characterization> 
13. Establish that APPOINTMENT is identifiable to the 
reader <characterization> 
resume developing the head term 
14. Have the environment select a term, here 
"appointment," from among the terms that survived 
syntactic selectivity <mapping> 
developing the modifiers of the head term 
15. Establish that the presentation specification for 
APPOINTMENT does not indicate that color, location, 
use, substance, size, place of origin or age should be 
expressed (7 inquiries) <characterization> 
developing the accompaniment modifier 
16. Establish that some kind of accompaniment of 
APPOINTMENT should be expressed 
<characterization> 
17. Obtain a symbol (WITHUS) representing the 
accompaniment knowledge to be expressed 
<decomposition> 
complete development of the head term 
18. Determine that the speaker wants the hearer to pay 
more than minimal attention to APPOINTMENT (thus 
cutting off further investigation of a substitution of 
"one" for "appointment") <characterization> 
developing the time period modifier 
19. Establish that the presentation specification of 
APPOINTMENT indicates that a time constraint 
should be expressed <characterization> 
20. Obtain a symbol (ONWEDNESDAYMORN) 
:eprasenting the time constraint to be expressed 
<decomposition> 
resume developing the determiner 
170 
21. Establish that no information about the proximity of 
APPOINTMENT should be expressed 
<characterization> 
22. Establish that information about the possessor of 
APPOINTMENT should be expressed 
<characterization> 
23. Obtain a symbol (JANE) representing the possessor of 
APPOINTMENT <decomposition> 
24. Establish that JANE is unitary <characterization> 
25. Establish that JANE does not represent a question 
variable <characterization> 
26. Obtain a symbol (SELF) representing the speaker 
<decomposition> 
27. Obtain a symbol (PUBLIC) representing the hearer of 
the entire nominal group <decomposition> 
28. Establish that SELF is not identical with or included in 
JANE <characterization> 
29. Establish that PUBLIC is not identical with or included 
in JANE <characterization> 
30. Establish that the gender of JANE is known 
<availability> 
31. Establish that the gender of JANE is female 
<characterization> 
finish developing the modifiers 
32.5stablish that there is no residue of unexpressed 
content in the presentation specification 
<characterization;> 
Using the answers to these inquiries, the grammar builds a 
structure consisting of four elements in an ordered sequence: 
"her," "appointment," ONWEDNESDAYMORN, 
WITHUS. 
the latter two representing conceptual elements tO be further 
developed in subsequent applications of the grammar. 
5 Relations between Operators 
Some operators are closely related in ways not suggested 
above. In particular, some pairs of operators are used together in 
a characteristic way: First an availability operator asks if certain 
information is available, for example, whether the location of an 
event is known. If a positive response is given, a decomposition 
inquiry asks for a symbol to represent the available information, 
such as the location. 
Almost all of the decomposition inquiries are paired with 
availability inquiries in this way. However, a few are not. For 
these, the grammar assumes the existence and separability of the 
information it requests.- The following are the exception cases: 
1. the identity of the speaker. 
2. the identity of the time of speaking, the "now" of 
tense. 
3. given an event to express in an independent clause, 
the identity of the time of occurrence of the event. 
4. given the need to generate a clause, the identity of the 
process portion (which will be realized in the main 
verb.) 
In addition, none of the mapping operators and none of the 
linking operators are paired. We see that the decomposition 
operators have little intellectual content, but the other kinds all 
contribute significantly. 
6 Demands on the Knowledge 
Representation 
Reviewing the inquiries, we can find several kinds of 
operations that are particularly difficult to support in explicit 
knowledge representations such as those currently used in AI or 
logic. 
One operator asks whether the existence of a particular 
entity is hvoothetical. Knowledge gained from this inquiry is useful 
in controlling contrasts such as the following: 
If they run to town, they will be sorry. 
If they are running to town, they will be sorry. 
Another operator asks about conjectural existence. It 
controls contrasts such as: 
They will run to town. 
They might run to town. 
In the first case the running to town is treated as definite 
but occurring in the future. 
Another asks whether an action to be expressed is habitual 
recurrent rather than a particular instance. Another group of 
inquiries seeks to determine the manner of performance of an 
action. Others deal with partial specifications and "question 
171 
variables" of the sort that are often realized by "wh" terms such 
as "what," "how," and "whether." Some operators control 
negation and quantification, which often cause representation 
problems. 
In addition to all of these potential problem sources, 
associated with inquiries whose responses will be difficult to 
determine, there are also many difficulties which do not arise from 
difficulties of representation. For example, knowing what to 
thematize and what to mark, knowing causes and beneficiaries, 
knowing which of several lexical items to use (after passing all 
syntactic and semantic tests), knowing what relations can be 
expressed as possession, knowing whether the reader is able to 
identify an entity in memory (for definite determination), 
discriminating near from far. all present difficulties without 
appearing to stress the capabilities of modern knowledge 
representations. 
Thus the inquiries can be used as an indication of what 
sorts of expansion a knowledge representation needs and as a 
guide to the ways in which current knowledge of discourse is 
inadequate to support text generation programming. 
7 Factoring the Text Generation Problem 
Inquiry semantics separates the problem of designing a 
text generator into parts which seem much more approachable 
than the problem as a whole. The grammar is separated from the 
environment by a tight interface which does not allow the 
grammar to access any elements of the environment directly. The 
inquiries are defined in a syntactically neutral or pre-syntactic 
form; answering them never requires knowledge of the syntax of 
the language being generated. As a result, the environment and 
the grammar can develop independently. This is particularly 
important today, since the technologies of the environment are 
very unstable, and we would like to be able to use a grammar in 
con!unction with several styles of knowledge representation. 
The environment is divided into the Knowledge Base and 
Text Plan parts, an informal but potentially very useful distinction. 
It tends to facilitate independent development of discourse 
planning methods. Truth-functional issues seem to be related 
largely to the Knowledge Base. 
The treatment of the lexicon separates a variety of lexical 
phenomena in separate, controlled ways: denotational 
appropriateness, syntactic features, and nonsyntactic 
.~onde=~otational attributes such as frequency and register, each 
receive distinctive treatment in NigeL 
8The Abstract Character of Inquiry 
Semantics 
In this section we compare inquiry semantics to other kinds 
of semantics, and also identify the nature of meaning in this 
framework. 
8.1 Comparative Semantics 
The inquiry-based semantics presented here contrasts 
with other accounts also called "semantics" in many ways, but it 
does not particularly compete with them. This semantics, as a way 
of theorizing, is an answer to the question "How can we 
characterize the circumstances under which it is appropriate to 
make each particular grammatical choice of a language?" 
It differs from other semantic approaches in that 
1. its scope is confined to grammar, rather than 
addressing linguistic behavior as a whole; 
2. it does not presume particular structures (deep or 
otherwise) in the environment; 
3. it is not particularly limited to issues reducible to 
questions of truth value; 
4. its scope includes nondeclarative, noninterrogative 
speech actions (including imperative, imprecation, 
and greeting functions) on a par with declarative and 
interrogative ones; 
5. it includes other functions of language in addition to 
the representational ones (such as the 
attention.direction functions); 
6. it is defined relative to generation rather than 
interpretation, but is not thereby "generative". 
This semantics is potentially compatible with other sorts, 
since it makes very few theoretical assumptions about the nature 
of language and communication. By encompassing every kind of 
syntactic construction, it is more inclusive than most. 
Nothing in inquiry semantics rules out any particular formal 
apparatus as the notation for the methods by which the 
environment responds to inquiries. Accounts of particular 
languages and grammars will give some informal guidance as to 
which sorts of methods will be perspicuous, and may rule out 
particular formalisms as response mechanisms for particular 
grammars. The topic is as yet unexplored. 
172 
8.2 The Nature of Meaning in inquiry Semantics 
We could assign meanings to any of several kinds of 
entities in this framework: grammatical features, collections of 
features, realizations of collections of features (i.e., structures), 
inquiry responses--or other possibilities. Our selection of a 
particular kind of entity as the locus of meaning depends on our 
intended use for that locus. We intend to use this notion of 
meaning to identify the ways in which minimal structurally-justified 
.~istinctives are responsive to their conditions of use. This 
selection does not preclude other selections for other purposes, 
and it certainly does not suggest that there are no other entities 
which are meaningful. 
We associate meanings with qrammal; qa feature~, in part 
because these are the controlling entities in the systemic 
framework. Given a systemic grammar, the syntactic structures 
~',nicn are produced depend entirely on the grammatical features 
which are chosen, and the opportunity to choose a grammatical 
feature also depends entirely on the grammatical features which 
are chosen, i.e., the entry conditions of the system in which "the 
feature occurs. So it is convenient to associate meaning with 
features, and to derive meanings for any other entity by the 
determinate derivational methods which the systemic framework 
provides. 
To state the meaning of a grammatical feature is to state 
the technical circumstances under which the feature is chosen. 
We identify these circumstances as the set of possible collections 
of inquiry responses which are sufficient to lead to the choice of 
the feature. The definitions of the systems of the grammar and 
their choice experts are thus sufficient to determine the meaning 
of every grammatical feature. 45 Ambiguity of a feature arises when 
there is more than one collection of relevant inquiry responses 
which leads to the choice of the feature. 
Differences of meaning reflect differences between 
collections of inquiry responses. In Nigel, for the features Singular 
and Plural, one of the collections of inquiry responses which leads 
4We do not stats the method here, since that involves many systemic details, but 
it is normally a rather straightforward matter for the Nige! grammar• More detail 
can be found in \[Mann 82, Mann & Matthiessen 83a, Mann & Matthiessen 8,3b\]. 
5The meanings of the features are not sufficient to find the sets of meanings 
which corres~ond to particular structures, since that requires the realization 
mapping of featureS to structureS. However, given the associations of features 
with realization operations, the structures for which a particular feature (or 
combination of features) is chosen can be identified, and so in principle the sets of 
techincal circumstances which can yield a particular string can be identified. 
to Singular contains a response "unitary" to MultiplicityQ, and a 
corresponding collection contains "multiple" as a response to 
MultiplicityQ, which leads to Plural. We can determine by 
inspection of the entire meanings that Singular and Plural exclude 
each other, and the determination could be made even if the 
features were not in direct opposition in the grammar. 
Notice that this approach is compatible with approaches to 
grammar other than traditional systemic grammar, provided that 
their optionality is reexpressed as alternation of features, with 
choice experts defined to identify the circumstances under which 
each option is chosen. 
Notice also that it is possible to have meanings in the 
~irammar which are ruled out by the environment, for example, by 
consistency conditions. A change in the environment's 
epistemology could lead to changes in how the grammar is 
employed, without changes in meaning, the grammar being more 
neutral than its user. 
Notice also that the collection of inquiry operators for a 
language is a claim concerning the semantic range of the 
grammar of that language, a characterization of what can be 
exDresssd syntactically. 
Notice finally that, given a grammar and an inquiry 
semantics of each of two different languages, the question of 
whether a particular sentence of one language has the same 
meaning as a particular sentence of the other language is an 
addressable question, and that it is possible in principle to find 
cases for which the meanings are the same. One can also 
investigate the extent to which a particular opposition in one 
language is an exact translation of an opposition in another. 
9 Conclusions 
The inquiry language as a level of abstraction provides a 
useful factoring of the text generation problem, isolating the 
grammar-intensive part. 
Development of inquiry language has led to the creation of 
new kinds of abstract elements that can be the operands of 
i;~quiries. Of these, presentation specifications and term sets have 
sufficiently novel scopes to suggest that they may be useful in 
defining relationships between grammar and language use. 
We have identified three dimensions of characterization 
that yield a convenient abstract structure for understanding 
inquiry language collectively (by categories of operands, 
173 
categories of operators and categories of subject matter.) These 
categorizations clarify the ways in which effective use of a 
grammar depends on processes and information outside of the 
grammar, including some ways which are not well controlled in 
available knowledge representations. 
Inquiry semantics contrasts with other theoretical entities 
I. 
also called "semantics" in many ways. It is potentially compatible 
with some other forms, but tends to be broader than many in 
including non-representational functions and non-declarative 
speech actions in its scope. 
Refe rences 
\[Berry 75\] Berry, M., Introduction to Systemic Linguistics: 
Structures and Systems. B. T. Batsford, Ltd., London, 1975. 
\[Berry 77\] Berry, M., Introduction to Systemic Linguistics: Levels 
and Links, B. T. Batsford, Ltd., London, 1977. 
\[de Joia & Stenton 80\] de Joia, A., and A. Stenton, Terms in 
Systemic Linguistics, Batsford Academic and Educational, 
Ltd., London, 1980. 
\[Fawcett 80\] Fawcett, R., Cognitive Linguistics and Social 
Interaction, Julius Groos Vertag and Exeter University Press, 
1980. 
\[Hailiday 76\] Halliday, M. A. K., System and Function in Language, 
Oxford University Press. London. 1976. 
\[Halliday & Hasan 76\] Halliday. M. A. K.. and R. Hasan. Cohesion 
in English, Longman, London, 1976. English Language 
Series, Title No. 9. 
\[Haltiday & Martin 81\] Halliday, M.A.K., and J. R. Martin (eds.), 
Readings in Systemic Linguistics, Batsford, London, 1981. 
\[Hudson 76\] Hudson, R. A., Arguments for a 
Non-Transformational Grammar, University of Chicago Press, 
Chicago, 1976. 
\[Mann 82\] Mann, W. C., The Anatomy of a Systemic Choice, 
USC/Information Sciences Institute, Marina del Rey, CA, 
Technical Report RR-82-104, October 1982. To appear in 
~iscourse Processes 
\[Mann 83\] Mann, William C°, An Overview of the Penman Text 
Generation System, USC information Sciences Institute, 
Marina del Rey, CA 90291., Technical Report RR.8,3.114, 
1983. To appear in the 1983 AAAI Proceedings. 
\[Mann & Matthiessen 83a\] Mann, W. C., and C. M. I. M. 
Matthiessen, Nigeh A Systemic Grammar for Text Generation, 
USC/Information Sciences Institute, RR-83.105, February 
1983. The papers in this report will also apoear in a 
forthcoming volume of the Advances in Discourse Processes 
Series, R. Freedle (ed.): Systemic Perspectives on Discourse: 
Selected Theoretical Papers from the 9th International 
Systemic Workshop to be published by Ablex. 
\[Mann & Matthiessen 83b\] Mann, William C. and Christian M. I. 
M. Matthiessen, An Overview of the Nige/ Text Generation 
Grammar, USC Information Sciences institute, Marina del 
Rey, CA 90291., Technical Report RR-8,3-113, 1983. 
174 
