TIRED of all those computers that answer phones and ask you to punch 1 for service and 2 for sales?Try calling Union Electric Company in St. Louis. After the usual prompt for touch-tone dialers, the computer says: "If you are calling from a rotary telephone, this system will recognize spoken numbers. Speak the word 'One. Customers who say "One" are prompted to say "One" again if they want to report an emergency, "Two" if they're moving in or out, "Three" if they want billing information. Then the computer routes the call to the appropriate live operator. Union Electric is in the forefront of companies that are starting to use computers that understand the spoken word. After years of promises and false starts, voice recognition is coming into its own. "This is moving from technology into applications," says Chris Seelbach, director of consulting at Probe Research Inc. in Cedar Knolls, N.J. Mr. Seelbach estimates the market for voice recognition is growing rapidly - from $50 million in 1990 to a predicted $120 million this year. By 1995, he expects the market for these systems to reach $500 million. "Speech recognition is something that's beginning to reach some fruition," says Dick Rabin, senior vice president of Vanguard Communications Corporation, a consulting firm in Morris Plains, N.J. "The technology is going to lead to much broader acceptance." Already, it is moving into specialized markets. For example: * Since January 1990, New York Telephone customers have made collect calls without a live operator. The computer records the caller's name, plays it back to the person on the other end of the line, and asks if he or she will accept the charges. If the person says yes, the computer puts the call through. * In May, EJV Brokerage Inc. launched an electronic trading service incorporating voice-recognition technology. Traders can trade government bonds using computer screens and either a keypad or a telephone handset. After less than an hour of training, the computer can understand about 50 spoken words from the trader, such as "Buy 15" and "Move bid up four." * Voice Control Systems of Dallas is working with Revenue Canada - Canada's version of the Internal Revenue Service - to set up an automated taxpayer information system. The twist: the computer understands French numbers if callers say "oui" at the prompt or English numbers if they say "yes." The technology still involves trade-offs at this point. Dragon Systems Inc. of Newton, Mass., builds machines for the handicapped that understand up to 30,000 words spoken by one person. Union Electric's system understands only "yes,no,oh," and the digits no matter who speaks them (even if they have an accent). Kurzweil Applied Intelligence Inc., a Waltham, Mass., company specializing in medical applications, requires doctors to pause briefly between each word when they dictate. Verbex Voice Systems Inc., of Edison, N.J., just introduced a dictating system that understands someone speaking words without any pauses. Eventually, better computers will overcome these limitations at a price that will attract more companies to voice recognition, analysts say. One encouraging sign of the technology's growing legitimacy is that AT&T, the telecommunications giant, has entered the market with a voice-recognition component to its interactive voice-response system. The system allows companies to route callers automatically even if they don't have a touch-tone phone. As the technology is perfected, the system could be used for a wide variety of services. Banking customers could transfer funds over the phone through a computer that would check their voice-print for security reasons. Consumers could order from an automated telephone catalog, make airline reservations, or dictate a letter to a computer. In five years, "I would bet that 30 to 40 percent of the companies would start deploying some level of the enhanced voice technology," says John Leikness, AT&T's product manager of voice messaging. Donald Karr, Union Electric's manager of telecommunication services, expects 20 to 25 percent of the utility's customers will use the system. "Most people still want to talk to a live person," he says.