For years computers with humanlike voices have been providing information -- the balance in a bank account, for example -- to those who seek it. But only gradually has speech feedback become both sophisticated and cheap enough to enable blind workers to manipulate computerized data in conventional office settings. Today inexpensive software programs link screens and keyboards with voice synthesizers such as DECTalk, a pioneering verbalizer that Digital Equipment (800-344-4825) recently scaled down for IBM-compatible PCs. With these programs a blind user, listening through earphones, can dexterously operate programs such as Lotus 1-2-3 or dBase.

Don't confuse voice synthesis with voice recognition. In the latter, a human utters words from a limited vernacular that the computer has been programmed to "understand." But here it's the computer that talks, reciting whatever is printed on its VDT by connecting snippets of prerecorded speech into words and sentences that replicate the patterns of ordinary discourse. Set up to evaluate context as well as grammar, screen-reading software is so discerning that, confronted in type with "St. Stephen's St.," it correctly pronounces each discrete st sound.

Like a touch-typist, a blind person works at an ordinary keyboard. The keyboard can be set to identify by speech such essentials as the name of the pressed key or the position of the cursor. Other features dedicated to blind users: spoken spreadsheet values, given by cell content or by the underlying formulas that calculate them; row and column information; split-screen functionality; talking calculators; capital letters distinguished by pitch; error-message recitation; and information on menu selections. Reacting to computers' expanding accessibility to the vision-impaired, software companies have begun printing business-program documentation in braille.

Advances will be rapid. Soon screen-reading capability is expected to be battery powered, so it can be adapted to laptops. And as computers become friendlier to all users via GUIs (graphic user interfaces), at least one lab, IBM's T.J. Watson Research Center, in Yorktown Heights, N.Y., is designing a talk mode that will allow blind people to respond to cartoons -- for example, a silly drawing of an eraser, rather than the typed command "delete."

The leading screen-reading programs for IBM-compatible PCs (prices are approximate and include a third-party voice synthesizer):

* Screen Reader, $1,800. IBM, 4111 Northside Pkwy., Atlanta, GA 30327; 800-426-2133.

* Vocal-Eyes, $1,595. GW Micro, 310 Racquet Dr., Fort Wayne, IN 46825; 219-483-3625.

* Business Vision, $895. Artic Technologies, 55 Park St., Troy, MI 48083; 313-588-7370. -- Robert A. Mamis

For information on this and other technological advances that accord self-sufficiency to disabled workers, contact the IBM Special Needs Information Referral Center, P.O. Box 2150-H06R1, Atlanta, GA 30301; 800-426-2133 (voice), 800-284-9482 (TDD).