Ch6-Formal Grammars of English

Ch6-Formal Grammars of English - Search and Decoding in...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Search and Decoding in Speech Recognition Formal Grammars of English February 13, 2012 Veton Këpuska 2 Formal Grammars of English Oldest Grammar written 2000 years ago by Panini for Sanskrit language. Geoff Pullum noted in a recent talk that “almost everything most educated Americans believe about English grammar is wrong”. February 13, 2012 Veton Këpuska 3 Formal Grammars of English Syntax: Syntaxis – Old Greek means “setting out together or arrangement” – it refers to the way the words are arranged together. Syntactic notions discussed previously: Regular Languages Computation of Probabilities of those representations of Regular Languages. Introduction of sophisticated notions of syntax and grammar that go beyond these simpler notions: Constituency Grammatical relations Subcategorization and dependency. February 13, 2012 Veton Këpuska 4 Constituency Groups of words may behave as a single unit or phrase – called constituent. Example: noun phrase often acting as a unit Single words: She, or Michael Phrases: The house Russian Hill, and A well-weathered three-story structure. Context-free grammars – a formalism that will allow us to model these constituency facts. February 13, 2012 Veton Këpuska 5 Grammatical Relations Formalization of ideas from traditional grammar such as SUBJECTS and OBJECTS, and other related notions. In the following sentence the noun phrase She is the SUBJECT and a mammoth breakfast is the OBJECT: She ate a mammoth breakfast. February 13, 2012 Veton Këpuska 6 Subcategorization and Dependency Relations Subcategorization and dependency relations refer to certain kinds of relations between words and phrases. For example the verb want can be followed by an infinitive, as in: I want to fly to Detroit , or a noun phrase, as in I want a flight to Detroit . But the verb find cannot be followed by an infinitive *I found to fly to Dallas . These are called facts about the subcategorization of the verb. February 13, 2012 Veton Këpuska 7 Context-Free-Grammars As we’ll see, none of the syntactic mechanisms that we’ve discussed up until now can easily capture such phenomena. They can be modeled much more naturally by grammars that are based on context-free grammars. Context-free grammars are thus the backbone of many formal models of the syntax of natural language (and, for that matter, of computer languages). As such they are integral to many computational applications including grammar checking, semantic interpretation, dialogue understanding, and machine translation. February 13, 2012...
View Full Document

{[ snackBarMessage ]}

Page1 / 122

Ch6-Formal Grammars of English - Search and Decoding in...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online