Encoding Lexicalized Tree Adjoining Grammars with a Nonmonotonic Inheritance Hierarchy

This paper shows how DATR, a widely used formal language for lexical knowledge representation, can be used to define an LTAG lexicon as an inheritance hierarchy with internal lexical rules. A bottom-up featural encoding is used for LTAG trees and this allows lexical rules to be implemented as covariation constraints within feature structures. Such an approach eliminates the considerable redundancy otherwise associated with an LTAG lexicon.Comment: Latex source, needs aclap.sty, 8 page

Implementing a formal model of inflectional morphology

International audienceInflectional morphology as a research topic lies on the crossroads of many linguistic subfields, such as linguistic description, linguistic typology, formal linguistics and computational linguistics. However, the subject itself is tackled with diverse objectives and approaches each time. In this paper, we describe the implementation of a formal model of inflectional morphology capturing typological generalisations that aims at combining efforts made in each subfield giving access to every one of them to valuable methods and/or data that would have been out of range otherwise. We show that both language description and studies in formal morphology and linguistic typology on the one hand, as well as NLP tool and resource development on the other benefit from the availability of such a model and an implementation thereof

Indexed Stems and Russian Word Formation: A Network Morphology Account of Russian Personal Nouns

Recent lexeme-based models have proposed that a lexeme carries an inventory of stems on which morphological rules operate. The various stems in the inventory are associated with different morphological rules, of both inflection and derivation. Furthermore, one stem may be selected by more than one rule. For this reason stems in the inventory are labeled with indexes, rather than being directly associated with a particular morphological function. It is claimed that an indexed-stem approach captures generalizations in the morphological system that would otherwise be missed. We argue that such an approach provides for greater generalization in the Russian morphological system. One area of Russian derivation that particularly lends itself to an indexed-stem approach is the highly productive system of personal-noun formation. We present a declarative account of Russian personal nouns that assumes indexed stems and show how such an account on the one hand obviates the need to posit either compound suffixes or concatenators and on the other dispenses with truncating/deleting rules. The account is couched within network morphology, a declarative lexeme-based framework that rests on the concept of default inheritance and is expressed in the computable lexical knowledge representation language D AT R

Pragmatics and word meaning

In this paper, we explore the interaction between lexical semantics and pragmatics. We argue that linguistic processing is informationally encapsulated and utilizes relatively simple ‘taxonomic’ lexical semantic knowledge. On this basis, defeasible lexical generalisations deliver defeasible parts of logical form. In contrast, pragmatic inference is open-ended and involves arbitrary real-world knowledge. Two axioms specify when pragmatic defaults override lexical ones. We demonstrate that modelling this interaction allows us to achieve a more refined interpretation of words in a discourse context than either the lexicon or pragmatics could do on their own.</jats:p