Grammar Formalisms Introduction Laura Kallmeyer, Timm Lichte, - PowerPoint PPT Presentation

Introduction to Grammar Formalisms Grammar Formalisms Introduction Laura Kallmeyer, Timm Lichte, Wolfgang Maier Universit¨ at T¨ ubingen 23.04.2007 Intro 1

Introduction to Grammar Formalisms Introduction Grammar Formalisms = “Grammar” + “Formalisms” Grammar: representation/description of (wellformed) structures of natural language ⇒ Grammars without formalisms ? Formalisms: mathmatically concise specification language Informal: A wellformed sentence consists of a subject, a verb and an object, where the subject precedes the verb and the object follows the verb. Formal: S → SU V OB Intro 2

Introduction to Grammar Formalisms Introduction The benefit of Grammar Formalisms (1) As is frequently pointed out but cannot be overemphasized, an important goal of formalization in linguistics is to enable subsequent researchers to see the defects of an analysis as clearly as its merits ; only then can progress be made efficiently. (Dowty, 1979, 322) linguistic theory grammar formalisms evaluation of the theory What is a good theory? “elegant, plausible, intuitive” ↓ size, expandability, strength of prediction Intro 3

Introduction to Grammar Formalisms Introduction The benefit of Grammar Formalisms (2) linguistic theory grammar formalisms computational application parsing problem recognition problem — structure problem the conveyed meaning problem the acquisition problem Intro 4

Introduction to Grammar Formalisms Introduction The landscape of Grammar Formalisms (1) generative rewriting formalisms: Context-Free Grammar (CFG) Tree-Adjoining Grammar (TAG) Lexical Functional Grammar (LFG) Transformational Grammar (GB), Minimalism proof-theoretic formalisms: Combinatorial Categorial Grammar (CCG) model-theoretic formalisms/constraint-based formalisms: Head-Driven Phrase Structure Grammar (HPSG) Intro 5

Introduction to Grammar Formalisms Introduction The landscape of Grammar Formalisms (2) Within Chomsky hierarchy : type 3 regular type 2 context-free CFG mildly context-sensitive TAG,CCG,Minimalist Grammar type 1 context-sensitive type 0 recursively enumerable HPSG,LFG,TG (or beyond) Intro 6

Introduction to Grammar Formalisms Introduction Inside and outside this lecture What we are going to cover: syntax foundations and applications of the following GFs: Tree Adjoining Grammar (TAG) , Head Driven Phrase Structure Grammar (HPSG),Combinatorial Categorial Grammar (CCG), Lexical Functional Grammar (LFG) What is not part of our concerns in this lecture: semantics, pragmatics, phonetics/phonology Transformational Grammar (GB), Minimalism corpus-driven approaches (quantitative linguistics) Intro 7

Introduction to Grammar Formalisms Introduction Schedule Introduction to TAG 1 Linguistic phenomena from English and German syntax 2 (description and TAG-analysis) Grammar implementation (XTAG,XMG) 3 Comparison of a sample of grammar formalisms 4 (TAG + HPSG,CCG,LFG) Intro 8