MASTER VOICES

According to Christopher Seelbach of Probe Research, a market-research firm that follows the voice-processing industry, applications of speech recognition fall into six main categories: 1.Very-small-vocabulary recognition to get information by telephone. Such a system might use only 0 through 9 and ``yes'' and ``no.''

2.Dialing for cellular telephones. ``[Car] phones offer a real hazard'' when people dial and drive at the same time, says Mr. Seelbach.

3.Voice-activated locks, where a voice print is used to verify an individual's identity.

4.Small-vocabulary-recognition systems for hands-free data entry in quality control and inventory.

5.Large-vocabulary systems for transaction processing. ``Financial trading is one particular market,'' Seelbach says. Shearson Lehman Hutton, a New York investment firm, is already using such a system.

6. Speech typewriters for creating letters, reports, and other documents. ``There are real questions about how quickly that is going to develop,'' he says.