Word spotting in conversational speech

Sperry Univac is developing a linguistically oriented system for locating key information-carrying words in conversational speech. The system first analyzes the speech acoustically, providing information on bandlimited energies and fundamental and formant frequencies. A prosodic analysis then indicates the location of syllables. Finally, a phonetic word verification technique is exercised on each syllable. Prestored acoustic properties characteristic of each phonetic segment of each keyword are compared against the incoming acoustic properties found at appropriate locations anchored within and around the syllables. Acoustic-phonetic parameter alignments exhibiting great similarity are announced as likely keyword occurrences. Current results are presented for this system, which is being developed and tested on noisy, bandlimited, conversational speech from a large and diverse speaker population.