Speech-generating device
[3] The content, organization, and updating of the vocabulary on an SGD is influenced by a number of factors, such as the user's needs and the contexts that the device will be used in.
Notable users of SGDs include Stephen Hawking, Roger Ebert, Tony Proudfoot, and Pete Frates (founder of the ALS Ice Bucket Challenge).
The first such aid was a sip-and-puff typewriter controller named the patient-operated selector mechanism (Naman) prototyped by Reg Maling in the United Kingdom in 1960.
In 1979, Mark Dahmke developed software for a vocal communication aid program using the Computalker CT-1 analog speech synthesizer with a microcomputer.
[13][14][15][16][17][18][19] The software utilized phonemes to generate speech, assisting individuals with communication impairments in constructing words and sentences.
[21][20][22][23] This early speech synthesis technology facilitated improved communication for Rush and was featured in a 1980 issue of LIFE Magazine.
[26] In the US, Dynavox (then known as Sentient Systems Technology) grew out of a student project at Carnegie-Mellon University, created in 1982 to help a young woman with cerebral palsy to communicate.
[27] Beginning in the 1980s, improvements in technology led to a greatly increased number, variety, and performance of commercially available communication devices, and a reduction in their size and price.
[30] In the past 20 or so years SGD have gained popularity amongst young children with speech deficiencies, such as autism, Down syndrome, and predicted brain damage due to surgery.
Neuro-linguists found that SGDs were just as effective in helping children who were at risk for temporary language deficits after undergoing brain surgery as it is for patients with ALS.
[33] Augmentative and alternative communication is typically much slower than speech,[6] with users generally producing 8–10 words per minute.
[40] Another approach to rate-enhancement is Dasher,[41] which uses language models and arithmetic coding to present alternative letter targets on the screen with size relative to their likelihood given the history.
[37] It is important to note that with technological advances made in the twenty-first century, fixed-display SGDs are not commonly used anymore.
Advantages of dynamic display devices include the availability of a much larger vocabulary, and the ability to see the sentence under construction[35] A further advantage of dynamic display devices is that the underlying operating system is capable of providing options for multiple communication channels, including cell phone, text messaging and e-mail.
[47] Low cost systems can also include a keyboard and audio speaker combination without a dynamic display or visual screen.
[49] The use of synthesized speech has increased due to the creation of software that takes advantage of the user's existing computers and smartphones.
AAC apps like Spoken or Avaz are available on Android and iOS, providing a way to use a speech-generating device without having to visit a doctor's office or learn to use specialized machinery.
[52] The content, organisation, and updating of this selection set are areas of active research and are influenced by a number of factors, including the user's ability, interests and age.
[4] Researchers Beukelman and Mirenda list a number of possible sources (such as family members, friends, teachers, and care staff) for the selection of initial content for a SGD.
A range of sources is required because, in general, one individual would not have the knowledge and experience to generate all the vocal expressions needed in any given environment.
Such processes work well for generating a core set of utterances or vocal expressions but are less effective in situations where a particular vocabulary is needed (for example, terms related directly to a user's interest in horse riding).
A typical technique to develop fringe vocabulary for a device is to conduct interviews with multiple "informants": siblings, parents, teachers, co-workers and other involved persons.
[4] Other researchers, such as Musselwhite and St. Louis suggest that initial vocabulary items should be of high interest to the user, be frequently applicable, have a range of meanings and be pragmatic in functionality.
[34] A number of research approaches have attempted to overcome this difficulty,[54] these range from "inferred input", such as generating content based on a log of conversation with a user's friends and family,[55] to data mined from the Internet to find language materials, such as the Webcrawler Project.
[58][59] Many recently developed SGDs include performance measurement and analysis tools to help monitor the content used by an individual.
[60][61] Similar concerns have been raised regarding the proposals for devices with automatic content generation,[57] and privacy is increasingly a factor in design of SGDs.
