Short for text-to-speech, a form of speech synthesis that converts text into spoken voice output. TTS systems were first developed to aid the visually impaired by offering a computer-generated spoken voice that would "read" text to the user.
TTS should not be confused with voice response systems. Voice response systems synthesize speech by concatenating sentences from a database of prerecorded words and are used for different purposes than TTS systems, which form sentences and/or phrases based on a language��s graphemes and phonemes. Voice response systems are limited to synthesizing sentences that contain only words that have been predetermined by the system. TTS systems, in contrast, are theoretically capable of "reading" any string of text characters to form original sentences.