Searching for part of speech tags that improve parsing models

Abstract

We introduce a technique for inducing a refinement of the set of part of speech tags related to verbs. We cluster verbs according to their syntactic behavior in a dependency structure setting. The set of clusters is automatically determined by means of a quality measure over the probabilistic automata that describe words in a bilexical grammar. Each of the resulting clusters defines a new part of speech tag. We try out the resulting tag set in a state-of-the art phrase structure parser and we show that the induced part of speech tags significantly improve the accuracy of the parser. © 2008 Springer-Verlag Berlin Heidelberg.