DEEP CASES FOR ADVERBIAL AND PREPOSITIOI~AL PHRASES 
Lieven Jaspaert 
Section of Applied Linguistics, Katholieke Universttett Leuven 
Blinds Inkomststraat 21, 3000 Leuven, Belgium 
This paper attempts to demonstrate the usefulness for 
Machine Translation of a case-oriented description of the syn- 
tactic and the semantic behavior of adverbial and prepositional 
constructions. 
Ee aim to modify and refine the existing descriptiohs of 
adverbs and prepositional phrases in order to put them to 
efficient use in Machine Translation. We hope to point out, 
furthermore, the desirability of incorporating deep case in- 
formation into the "interface structure" of a Machine Trans- 
lation system. 
I. Task-svecific requirements on parsing 
Parsing sentences for translation purposes is bound to 
differ i~ significant ways from parsing natural language for 
other tasks. In this paragraph, we will formulate a n,,mbar of 
translation-speclfio requirements on natural language analy- 
sis which, moreover, will be of particular interest in the 
discussion of the issues in the following paragraphs. 
2. Surface cases, deep cases and conceptual caqes 
A much debated issue in AI is the desirable depth of the 
case system employed In natural language understanding 
programs. From the preceding paragraph, however, it will have 
become apparent that, in Machine Translation, one could better 
- 137 - 
make use of various case systems of increasing depth. In 
this paragraph, we will be concerned with the definition of 
the three types of oases we consider to be adequate for trans- 
lational purposes: (i) surface cases reflect the dependency 
relation~ which exist between constituents and their gover- 
nors; (ii) deep cases provide information about the valency 
boundnese of the participants in the predication; (ili) con- 
ceptusl cases are language-independent values which give in- 
formation about the states of affairs people talk about. 
3. Deep ca~eq for adverbial and prepositional phrases 
It is common practice in valency grammar to assign the 
properties + valency-bound or - valency-bound to constituents. 
We hope to show that this dichotomy is inadequate for dealing 
with natural language in general, and with adverbial end pre- 
positional phrases in particular. The discussion will aim at 
introducing a third property to the set of deep cases ccmnonly 
used: the "trenspropositional case °. 
The main part of this Section will be devoted to the de- 
finition of the transpropositional case. We will point out the 
descriptive and computational advantages of the three-case 
system proposed, on the basis of examples. This will lead to a 
classification of adverbial and prepositional constructions 
which differs in a considerable way from the one traditionally 
used in linguistics. F~ther attention will be expended to 
constructions other than adverbial and prepositional ones, 
which should as well be labeled trsnspropoeitional. 
4. Conclusion 
In the final paragraph, we will briefly sketch the need 
of introducing the transpropositional case into the set of 
deep case relations, by showing that its omission would lead 
to bad translations. 
- 138 - 
