Ch6-Formal Grammars of English

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

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Search and Decoding in Speech  Recognition Formal Grammars of English
Background image of page 1

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

View Full Document Right Arrow Icon
2/13/12 Veton Këpuska 2 Formal Grammars of English u Oldest Grammar written 2000 years ago by Panini for Sanskrit  language. u Geoff Pullum noted in a recent talk that “almost everything most  educated Americans believe about English grammar is wrong”.
Background image of page 2
2/13/12 Veton Këpuska 3 Formal Grammars of English u Syntax: n Syntaxis – Old Greek means “setting out together or arrangement” –  it refers to the way the words are arranged together. u Syntactic notions discussed previously: n Regular Languages n Computation of Probabilities of those representations of Regular  Languages. u Introduction of sophisticated notions of syntax and grammar that  go beyond these simpler notions: n Constituency n Grammatical relations n Subcategorization and dependency.
Background image of page 3

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

View Full Document Right Arrow Icon
2/13/12 Veton Këpuska 4 Constituency u Groups of words may behave as a single unit or phrase – called  constituent. n Example:  noun phrase  often acting as a unit n Single words:  u She, or  u Michael n Phrases:  u The house u Russian Hill, and u A well-weathered three-story structure. u Context-free grammars – a formalism that will allow us to model  these constituency facts.
Background image of page 4
2/13/12 Veton Këpuska 5 Grammatical Relations u Formalization of ideas from traditional grammar such as  SUBJECTS and OBJECTS, and other related notions.  u In the following sentence the noun phrase  She  is the SUBJECT  and  a mammoth breakfast  is the OBJECT: n She ate a mammoth breakfast.
Background image of page 5

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

View Full Document Right Arrow Icon
2/13/12 Veton Këpuska 6 Subcategorization and Dependency  Relations u Subcategorization  and  dependency relations  refer to certain  kinds of relations between words and phrases.  u For example the verb  want  can be followed by an infinitive, as in: n I want to fly to Detroit , or a noun phrase, as in  n I want a flight to Detroit u But the verb  find  cannot be followed by an infinitive n *I found to fly to Dallas n These are called facts about the  subcategorization  of the verb.
Background image of page 6
2/13/12 Veton Këpuska 7 Context-Free-Grammars u 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.  u 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  n grammar checking,  n semantic interpretation,  n dialogue understanding, and  n machine translation. 
Background image of page 7

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

View Full Document Right Arrow Icon
2/13/12 Veton Këpuska 8 Context-Free-Grammars u
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 130

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

This preview shows document pages 1 - 9. Sign up to view the full document.

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