Paper: Immediate-Head Parsing For Language Models

ACL ID P01-1017
Title Immediate-Head Parsing For Language Models
Venue Annual Meeting of the Association of Computational Linguistics
Session Main Conference
Year 2001

We present two language models based upon an “immediate-head” parser — our name for a parser that conditions all events below a constituent c upon the head of c. Whileallofthemost accurate statistical parsers are of the immediate-head variety, no previous grammatical language model uses this technology. The perplexity for both of these models significantly improve upon the trigram model base-line as well as the best previous grammar- based language model. For the better of our two models these improvements are 24% and 14% respectively. We also suggest that improvement of the un- derlying parser should significantly im- prove the model’s perplexity and that even in the near term there is a lot of po- tential for improvement in immediate- head language models.