Using a connectionist model in a syntactical based language model

Abstract

We investigate the performance of the Structured Language Model when one of its components is modeled by a connectionist model. Using a connectionist model and a distributed representation of the items in the history makes the component able to use much longer contexts than possible with currently used interpolated or backoff models, both because of the inherent capability of the connectionist model to fight the data sparseness problem, and because of the only sub-linear growth in the model size when increasing the context length. Experiments show significant improvement in perplexity and moderate reduction in word error rate over the baseline SLM results on the UPENN treebank and Wall Street Journal (WSJ) corpora respectively. The results also show that the probability distribution obtained by our model is much less correlated to regular N-grams than the baseline SLM model.