Automatic recognition of the part-of-speech for english texts

摘要

A method is introduced to recognize the part-of-speech for English texts using knowledge of linguistic regularities rather than voluminous dictionaries. The algorithm proceeds in two steps; in the first step information concerning the part-of-speech is extracted from each word of the text in isolation using morphological analysis as well as the fact that in English there are a reasonable number of word endings which are characteristic of the part-of-speech. The second step is to look at a whole sentence and, using syntactic criteria, to assign the part-of-speech to a single word according to the parts-of-speech and other features of the surrounding words. In particular, those parts-of-speech which are relevant for automatic indexing of documents, i.e. nouns, adjectives, and verbs, are recognized. An application of this method to a large corpus of scientific text showed the result that for 84% of the words the part-of-speech was identified correctly and only for 2% definitely wrong; for the rest of the words ambiguous assignments were made. Using only word lists of a limited extent, the technique thus may be a valuable tool aiding automatic indexing of documents and automatic thesaurus construction as well as other kinds of natural language processing.