Specializing Word Embeddings (for Parsing) by Information Bottleneck (Extended Abstract)

Specializing Word Embeddings (for Parsing) by Information Bottleneck (Extended Abstract)

Xiang Lisa Li, Jason Eisner

Proceedings of the Twenty-Ninth International Joint Conference on Artificial Intelligence
Sister Conferences Best Papers. Pages 4745-4749. https://doi.org/10.24963/ijcai.2020/658

Pre-trained word embeddings like ELMo and BERT contain rich syntactic and semantic information, resulting in state-of-the-art performance on various tasks. We propose a very fast variational information bottleneck (VIB) method to nonlinearly compress these embeddings, keeping only the information that helps a discriminative parser. We compress each word embedding to either a discrete tag or a continuous vector. In the discrete version, our automatically compressed tags form an alternative tag set: we show experimentally that our tags capture most of the information in traditional POS tag annotations, but our tag sequences can be parsed more accurately at the same level of tag granularity. In the continuous version, we show experimentally that moderately compressing the word embeddings by our method yields a more accurate parser in 8 of 9 languages, unlike simple dimensionality reduction.
Keywords:
Natural Language Processing: Embeddings
Natural Language Processing: Tagging, chunking, and parsing
Natural Language Processing: Natural Language Processing