People are hearing ‘voices’

The next time a consumer hears a voice thanking him for the call, that voice may be generated by a computer — and the caller might not even know it.

The quality and sound of computer-synthesized voices not only continues to improve, but their uses also are expanding, including helping the physically disabled.

Even some “podcasters” — Internet enthusiasts who broadcast audio via the Web — are turning to this technology to convert text into downloadable bits of audio.

Professor J.P. Auffret, director of George Mason University’s technical management program, recalls not so long ago hearing an artificial voice ringing out at an Atlanta airport. That voice, which he describes as something out of “Star Trek,” sounded far more human during a recent trip through Georgia.

Mr. Auffret says companies are approaching voice synthesis from different angles. Some, such as Microsoft, try to unlock the mysteries of the human voice with algorithms to duplicate how speech is created. Others, including AT&T;’s Natural Voices program, break down the elements of language into short snippets of human speech and let powerful computers choose which of these building blocks should be assembled into sentences.

Under this procedure, voice actors read hours of scripts that are recorded and dissected into smaller pieces and mapped to coincide with various phonemes, or the tiniest phonetic unit in a language capable of conveying any meaning. Then, computers must reassemble the words into sentences, taking care to note the varying inflections based on where the snippets go in a sentence or if the sentence is a question.

“Now, it’s possible to have much longer sentences, much more involved text which almost sounds natural,” Mr. Auffret says.

Software supplied by AT&T;’s Natural Voices program plays a considerable role in consumer applications such as customer relations as well as aiding the handicapped.

Juergen Schroeter, director of speech algorithms and engines in AT&T; labs-research, says his company’s ties to artificial speech started with Voder, an attempt displayed at the 1939 World’s Fair in New York.

Yet Mr. Schroeter admits that as few as six years ago, the company’s text-to-speech vocals still sounded “unnatural.”

Today, computer voice technology helps a variety of groups, from the disabled to the U.S. military. Enhanced text-to-speech software brings books alive for blind readers, while computer voices are helping soldiers communicate with the locals wherever their platoon might be.

What the technology still can’t convincingly capture is raw emotion.

Mr. Schroeter says his company has “closed the gap already for short [computer voice] responses of three or four words. We can perfectly say, ‘thank you,’ for example.”

Longer sentences with varied inflections remain a problem, as does trying to make synthesized voices express a variety of crucial emotions.

Rick Ellis, president of the North Carolina-based NextUp.com, says computer voice technology lets a relatively small company like his offer a variety of services that a decade ago would have seemed impossible.

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