A comparison of time conditioned and word conditioned search techniques for large vocabulary speech recognition

Compares the search effort required by the word-conditioned and the time-conditioned tree search methods. Both methods are based on a time-synchronous, left-to-right beam search using a tree-organized lexicon. Whereas the word-conditioned method is well-known and widely used, the time-conditioned method is novel in the context of 20,000-word vocabulary recognition. We extend both methods to handle trigram language models in a one-pass strategy. Both methods were tested on a train schedule inquiry task (1,850 words, telephone speech) and on the North American Business development corpus (20,000 words) of November 1994.