Syntax analysis
Ralph Grishman · Computational Linguistics · 1986
The role of syntax analysis Syntax analysis performs two main functions in analyzing natural language input: Determining the structure of the input . In particular, syntax analysis should identify the subject and objects of each verb and determine what each modifying word or phrase modifies. This is most often done by assigning a tree structure to the input, in a process referred to as parsing . Regularizing the syntactic structure . Subsequent processing (i.e., semantic analysis) can be simplified if we map the large number of possible input structures into a smaller number of structures. For example, some material in sentences (enclosed in brackets in the examples below) can be omitted or ‘zeroed’: John ate cake and Mary [ate] cookies. … five or more [than five] radishes … He talks faster than John [talks]. Sentence structure can be regularized by restoring such zeroed information. Other transformations can relate sentences with normal word order (‘I crushed those grapes. That I like wine is evident.’) to passive (‘Those grapes were crushed by me.’) and cleft (‘It is evident that I like wine.’) constructions, and can relate nominal (‘the barbarians' destruction of Rome’) and verbal (‘the barbarians destroyed Rome’) constructions. Such transformations will permit subsequent processing to concern itself with a much smaller number of structures. […]