Abstract

Probabilistic syntactic parsing has made rapid progress, but is reaching a performance ceiling. More semantic resources need to be included. We exploit a number of semantic resources to improve parsing accuracy of a dependency parser. We compare semantic lexica on this task, then we extend the back-off chain by punishing underspecified decisions. Further, a simple distributional semantics approach is tested. Selectional restrictions are employed to boost interpretations that are semantically plausible. We also show that self-training can improve parsing even without needing a re-ranker, as we can rely on a sufficiently good estimation of parsing accuracy. Parsing large amounts of data and using it in self-training allows us to learn world knowledge from the distribution of syntactic relation. We show that the performance of the parser considerably improves due to our extensions.