Glossary
Searchable terminology from accessibility, web standards, and related fields.
68 results found in AAC.
- Prediction Utilization (PU)
- The percentage of opportunities where a user accepts a word prediction rather than continuing to type the word manually. Prediction utilization reflects user trust in a prediction system—higher qualit…
- QuickFire (Quick Phrases, Quick Response Buttons)
- Pre-programmed short phrases or responses stored on AAC devices that can be accessed and played quickly with minimal navigation, typically arranged on a single page for rapid access. QuickFire phrases…
- Remnant book (remnant scrapbook, memory book)
- An AAC strategy that uses collected physical artifacts—such as ticket stubs, photos, business cards, and other tangible items—organized in a book or album to support communication for people with apha…
- Response Time (Reaction Time, Tact)
- The time elapsed between the presentation of a stimulus and the user's physical response, typically measured in milliseconds. In scanning-based AAC, response time (often called Tact) is the interval b…
- Row-Column Scanning (RCS, Grid Scanning, Two-Switch Scanning)
- The most widely used single-switch selection method for augmentative and alternative communication (AAC) devices and on-screen keyboards. Options are arranged in a two-dimensional grid, and the interf…
- Scanning (Switch Scanning, Automatic Scanning)
- An indirect selection method used in augmentative and alternative communication (AAC) and assistive technology where items (letters, words, or commands) are highlighted sequentially by the system, and…
- Scanning Delay (Tscan, Scan Rate, Dwell Time)
- The time interval a scanning system waits before automatically advancing to highlight the next item. Setting scanning delay appropriately is critical for switch access users: too short causes selectio…
- Scanning System (Automatic Scanning, Group Scanning, Row-Column Scanning)
- An assistive technology input method in which selectable items are sequentially highlighted on screen, and the user activates a switch (or other simple input) when the desired item is highlighted. Sca…
- Semantic Redundancy (Redundant Multimodal Input)
- A design strategy in multimodal interfaces where the same command or message is conveyed simultaneously through multiple input channels, each independently signalling the user's intent. For example, a…
- Single Switch (Single Switch Access, One Switch)
- An assistive technology input device that provides a single binary action — on or off — enabling people with severe motor impairments to interact with computers and communication devices. Switches can…
- Single-Message AAC Device (BIGmack, Single-Switch Communicator, Voice Output Communication Aid)
- A simple augmentative and alternative communication (AAC) device that records and plays back a single message when activated, typically via a large button or switch. Examples include the BIGmack Switc…
- Speech Generating Device (SGD, Voice Output Communication Aid, VOCA)
- An electronic device used in augmentative and alternative communication that produces speech output, either through pre-recorded messages or text-to-speech synthesis. Speech generating devices range f…
- Speech Neuroprosthesis (Speech BCI, Speech Brain-Computer Interface)
- A brain-computer interface that decodes neural activity associated with attempted or imagined speech and converts it into text, synthesized voice, or both. Speech neuroprostheses are designed for peop…
- Speech-Generating Device (SGD, Voice Output Communication Aid, VOCA)
- An electronic AAC device that produces spoken output from text or symbol input, enabling people with speech disabilities to communicate verbally with others. Speech-generating devices range from dedic…
- Step-by-Step Device (Sequential Message Device, Step-by-Step Communicator, SBS)
- A simple, single-switch augmentative and alternative communication (AAC) device that stores a sequence of pre-recorded voice messages and plays them back one at a time with each button press. Step-by-…
- Switch Keyboard (Scanning Keyboard, On-Screen Scanning Keyboard)
- A switch keyboard is a virtual keyboard interface designed for people with severe motor disabilities who cannot use a standard keyboard or pointing device. It works through a scanning mechanism: a cur…
- Symbol-based AAC (Picture-based AAC, Pictographic AAC, Picture Communication Symbols)
- Symbol-based AAC refers to augmentative and alternative communication systems whose vocabulary is represented by graphic symbols, line drawings, photographs, or pictograms rather than (or alongside) w…
- Technical Agency
- Technical agency, in the context of augmentative and alternative communication (AAC), refers to an individual's ability to actively participate in and contribute to a conversation through direct actio…
- Text Gloss (Text Glosses)
- In Augmentative and Alternative Communication (AAC), a text label or annotation associated with a visual symbol (such as an icon or pictogram) on a communication device. The text gloss serves two purp…
- Trigram (3-gram)
- A sequence of three consecutive words used in statistical language modeling for word prediction. Trigram models predict the next word based on the two preceding words, capturing more context than simp…