Listeners' preference for computer-synthesized speech over natural speech of people with disabilities

There are few controlled experimental studies that examine reactions to people with speech disabilities. We conducted 2 studies designed to examine participants' reactions to persuasive appeals delivered by people with physical disabilities and mild to moderate dysarthria.

Research participants watched video clips delivered by actors with bona fide disabilities and subsequently rated the argument, message, and the speaker. The first study (n = 165) employed a between-groups design that examined reactions to natural dysarthric speech, synthetic speech as entered into a keyboard by hand, and synthetic speech as entered into a keyboard with a headwand. The second study (n = 27) employed a within-groups design that examined how participants reacted to natural dysarthric speech versus synthetic speech as entered into a keyboard by hand.

Both of these studies provide evidence that people rated the argument, message, and speaker more favorably when people with disabilities used synthetic speech than when they spoke in their natural voice.

The implications are that although people react negatively to computer-synthesized speech, they prefer it to and find it more persuasive than the speech of people with disabilities. This appears to be the case even if the speech is only moderately impaired and is as intelligible as the synthetic speech. Hence, the decision to use synthetic speech versus natural speech can be further complicated by an understanding that even the intelligible speech of people with disabilities leads to more negative reactions than synthetic speech.