Glossary

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Non-Verbal Vocalization(also: Non-Speech Vocalization, Vocal Gesture, Non-speech Vocalisation)

A sound produced by the voice that is not a spoken word, such as a sustained vowel sound ("Ahhhhh"), hum, or other vocal noise. In assistive technology and alternative input contexts, non-verbal vocalizations can serve as continuous control signals for cursor movement or other…

Nontraditional Assistive Technologies(also: NTATs, Nontraditional Input Technologies)

Input technologies that use physiological signals rather than physical movement to control computers, providing access for people who cannot use traditional devices like keyboards, mice, or even eye-tracking systems. NTATs include brain-computer interfaces (using EEG or fNIR),…

On-Screen Keyboard(also: Virtual Keyboard, Software Keyboard, OSK)

A software application that displays a visual representation of a keyboard on the computer screen, allowing users to type by selecting keys with a pointing device, head tracker, eye gaze system, or switch. On-screen keyboards are essential assistive technology for people who…

Point-of-Gaze(also: POG, Gaze Point, Point of Regard)

Point-of-gaze is the location on a display, scene, or object at which a user's eye is currently fixating, typically reported by an eye tracker as a stream of (x, y) screen coordinates sampled at rates between 30 and several hundred hertz. Raw point-of-gaze data is noisy and…

Predictive Disambiguation(also: Dictionary-based Predictive Disambiguation, DBPD, Word Disambiguation)

Predictive disambiguation is the class of text-entry techniques in which each user input event is intentionally ambiguous (one keystroke covers several possible letters, one swipe covers many possible paths) and software resolves the ambiguity into a most-likely word using a…

Silent Speech(also: Silent Speech Interface, SSI)

Communication technologies that generate intelligible speech from non-acoustic signals produced during the intent or attempt to speak, without requiring audible voicing. Input modalities include surface electromyography of articulatory muscles, ultrasound tongue imaging,…

Sony Access Controller(also: PlayStation Access Controller, Project Leonardo)

A customisable game controller released by Sony in 2023 for the PlayStation 5, designed for players with limited motor control. The Access Controller is a circular unit with swappable button caps, long-throw levers, adjustable stick positioning, and four 3.5mm ports for external…

Speech-Based Cursor Control(also: Voice Cursor Control, Speech-Driven Pointing)

A method of controlling a computer's pointing cursor using spoken voice commands rather than a mouse, trackpad, or other physical pointing device. Users speak directional commands (such as "move left," "move up") to start cursor movement and a stop command to halt it, then issue…

Speech-Based Cursor Movement(also: Voice-Controlled Cursor, Voice Cursor Control)

A technique for moving the on-screen cursor using voice commands rather than physical manipulation of a pointing device. Speech-based cursor movement systems typically use one of two approaches: discrete specification, where the user speaks a command to jump the cursor to a…

Subvocal Input(also: Subvocal Control, Subvocalisation Input)

An input method that uses very quiet or nearly silent vocalisations — sounds produced with minimal vocal effort that are typically inaudible to nearby people. Subvocal input includes techniques such as humming, whispering, or producing sounds detectable only by bone-conduction…

Surface Electromyography(also: sEMG, Surface EMG)

A non-invasive technique for measuring the electrical activity produced by skeletal muscles, using electrodes placed on the skin over the muscle. Surface EMG is used in biomechanics, prosthetic control, rehabilitation, and — increasingly — as an input modality for accessible…

Switch Scanning(also: Switch Access, Scanning Input)

An alternative input method in which items on a screen are sequentially highlighted and the user activates a switch to select the desired item when it is highlighted. Switch scanning is used by people with significant motor impairments who cannot use direct touch, a mouse, or a…

Syntax-Directed Editor(also: Structure Editor, Syntax-Aware Editor)

A code editor that understands the formal grammar of a programming language and uses this knowledge to guide editing operations. Unlike plain text editors, syntax-directed editors treat source code as a structured tree of language constructs rather than a sequence of characters.…

Trackball

A trackball is a pointing device consisting of a ball housed in a stationary socket that the user rotates to move the on-screen cursor, with buttons nearby for clicking. Unlike a mouse, a trackball does not require arm movement across a surface, making it valuable for people…

Vocal Joystick(also: VJ, Voice Joystick)

A voice-based human-computer interface that uses continuous non-verbal vocal sounds (rather than spoken words) to provide proportional, real-time control of devices, cursors, or robotic systems. The Vocal Joystick engine extracts pitch, loudness, and vowel quality from the…

Xbox Adaptive Controller(also: XAC)

A Microsoft-manufactured game controller designed for players with limited mobility. It provides a large flat-surface form factor with two oversized programmable buttons and 19 external 3.5 mm jacks plus USB ports, so it can be connected to a wide range of external switches,…