Word boundary acoustic units

An improved speech recognition system of the type employing word models, wherein the improvement comprises:

• a set of word models for modeling vocabulary to be recognized, each word model being associated with a word in the vocabulary, each word in the vocabulary considered as a sequence of phones including a first phone and a last phone, wherein each word model begins in the middle of the first phone of its associated word and ends in the middle of the last phone of its associated word;
• and
• a set of word connecting models for modeling acoustic transitions between the middle of a word's last phone and the middle of an immediately succeeding word's first phone.

An improved method of a speech recognition system for recognizing an input utterance of spoken words, the improvement comprising:

• modeling vocabulary to be recognized with a set of word models, each word model being associated with a word in the vocabulary, each word in the vocabulary being considered as a sequence of phones including a first phone and a last phone, wherein each word model begins in the middle of the first phone of its associated word and ends in the middle of the last phone of its associated word;
• and
• modeling acoustic transitions between the middle of a word's last phone and the middle of an immediately succeeding word's first phone with a set of word connecting models.