Use of Syntax in the Analysis of Connected Speech Utterances

A method to analyze connected speech utterances using a finite-state grammar acting on a restricted vocabulary is proposed. The sentences are commands to a computer-controlled HAND-EYE system able to find blocks and stack them. Audio input to the system is provided through an analog speech preprocessor producing six parameters every 10 msec. Using these parameters, a computer procedure segments the whole utterance and generates a sound description. The decoding of the commands is done by scanning the speech-utterance description forward and backward looking for “known” (previously learned) words. The vocabulary is chosen so that the word boundaries are always at a minimum of amplitude or at a fricative-type segment. The word recognition is done on a best-match-type comparison scheme acting on prelearned word representations. At any step, feedback from the grammar is used to eliminate from the matching process the syntactically incorrect word representation. The program “understands” the key words of an utterance like: “PICK UP EVERY MEDIUM BLOCK STARTING AT THE BOTTOM RIGHT CORNER” in about 10 sec.