For people with cognitive, learning, speech, and other impairments, the use of augmentative and alternative communication devices (“AAC”) is an important means of augmenting the ability to communicate in a variety of contexts. AAC is a broad term for a variety of devices that enable the user to effectively communicate, aid in the expression of needs and wants, and transfer information. Useful devices range from low technology typewriters and special boards with pictures or words where a person can point to convey his or her meaning, to sophisticated speech computers with touch screens and a speech synthesizer (text-to-speech (TTS)) system that produces sounds imitating the human voice.
- Speech synthesizer. A speech synthesizer translates written text into verbal words so that individuals may communicate verbally by typing messages, which are read aloud by the speech synthesizer. Pre-programmed instant phrases are recorded into the device, and can be played back by hitting the designated button. Speech synthesizers also allow individuals with vision impairments to read written documents by listening to them. Most synthesizers have several voices to choose from, including male, female, and child voices, and also allow the adjustment of pitch and rate of speech.