Petr Sgall

A scale of context sensitive languages: Applications to natural language

The classes of languages Ti are defined, i being a natural number, for which it is proved that Ti is a proper subset of T i+1, and a proper subset of context-sensitive languages, if Ti is the set of all context-free languages and Ti+1 is the set of all possible translations from Ti by means of a so-called linear deterministic pushdown store transducer; the formal mechanism is close enough to the so-called functional generative description, which has already been applied to large subsets of natural languages.

The ordering principle

Abstract The objective of the present paper is to point out the existence of a principle governing the ordering of a sentences major constituents (Section 1). This principle is closely related to the pragmatically based (though linguistically structured) topic-focus articulation of the (meaning of a) sentence, and therefore we also mention the operational tests used to analyze this articulation and characterize the semantic relevance of topic and focus, and of the communicative dynamism (CD) (section 2). We show how these phenomena can be economically described on the basis of Chomskys theta theory, if the ordering principle is treated by the categorial component (Section 3).

A Functional Approach to Syntax in Generative Description of Language

Come with us to read a new book that is coming recently. Yeah, this is a new coming book that many people really want to read will you be one of them? Of course, you should be. It will not make you feel so hard to enjoy your life. Even some people think that reading is a hard to do, you must be sure that you can do it. Hard will be felt when you have no ideas about what kind of book to read. Or sometimes, your reading material is not interesting enough.

The Current Status of the Prague Dependency Treebank

The Prague Dependency Treebank (PDT) project is conceived of as a many-layered scenario, both from the point of view of the stratal annotation scheme, from the division-of-labor point of view, and with regard to the level of detail captured at the highest, tectogrammatical layer. The following aspects of the present status of the PDT are discussed in detail: the now-available PDT version 1.0, annotated manually at the morphemic and analytic layers, including the recent experience with post-annotation checking; the ongoing effort of tectogrammatical layer annotation, with a specific attention to the so-called model collection; and to two different areas of exploitation of the PDT, for linguistic research purposes and for information retrieval application purposes.

Identifying topic and focus by an automatic procedure

An algorithm for automatic identification of topic and focus of the sentence is presented, based on dependency syntax and using written input, which is much more ambiguous than spoken utterance.

Tagging of very large corpora: topic-focus articulation

After a brief characterization of the theory of the topic-focus articulation of the sentence (TFA), rules are formulated that determine the assignment of appropriate values of the TFA attribute in the process of syntactico-semantic tagging of a very large corpus of Czech.

DEPENDENCY SYNTAX - A CHALLENGE

Dependency grammar, although now elaborated only by small groups of linguists, has several advantages if compared with the majority approaches, based on constituency and on categorial grammars: the dependency trees (and the corresponding representations covering also the relations of coordination and of apposition) are more economical than most kinds of P-markers; a perspicuous treatment of the topic-focus articulation is made possible, since word order is connected more directly with the scale of communicative dynamism than with syntactic relations. Problems of generative power, of deletion, of anaphoric relations, etc., do not appear to be more serious with dependency grammar than with other approaches.

ON THE ROLE OF LINGUISTIC SEMANTICS

We want to present some support for the suggestion that a counterpart of Carnaps intensional structure may be specified, for natural language, as the semantic representations of sentences, if belief (and other intensional) contexts are kept apart from metalinguistic assertions. Semantic representations should include the topic/focus articulation and other empirically based issues that can be checked linguistically, while the interplay of meaning postulates and a translation procedure should account for the relationship between semantic representations and propositions. It is also suggested that the relationship between concepts and objects ist not fully symmetrical to that between propositions and truth values.

Towards a Pragmatically Based Theory of Meaning

In the context of our conference, my contribution will probably seem to be a little bit old fashioned, since it is not directly based on an analysis of speech acts. I am afraid, however, that the relationships between speech act theory and semantics are still to be studied from the viewpoint of ‘classical’ semantics also.

Topic-focus and Salience

Most of the current work on corpus annotation is concentrated on morphemics, lexical semantics and sentence structure. However, it becomes more and more obvious that attention should and can be also paid to phenomena that reflect the links between a sentence and its context, i.e. the discourse anchoring of utterances. If conceived in this way, an annotated corpus can be used as a resource for linguistic research not only within the limits of the sentence, but also with regard to discourse patterns. Thus, the applications of the research to issues of information retrieval and extraction may be made more effective; also applications in new domains become feasible, be it to serve for inner linguistic (and literary) aims, such as text segmentation, specification of topics of parts of a discourse, or for other disciplines.