Glossary

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DALL-E(also: DALL-E 2, DALL-E 3, DALLE)

A family of text-to-image generative AI models developed by OpenAI that produces images from natural-language prompts. DALL-E models are widely used by content creators, including people with disabilities, to generate visuals without photography or illustration skills, but they…

DECTalk

A text-to-speech synthesis system originally developed by Digital Equipment Corporation in the 1980s, using rule-based formant synthesis to generate speech from text input. DECTalk offered several preset voices (including "Paul" and "Betty") and was widely adopted in AAC…

DIY AAC(also: Do-It-Yourself AAC, Self-Made AAC, Bespoke AAC)

Augmentative and alternative communication tools created or significantly customized by the users themselves rather than prescribed by clinicians or purchased as commercial products. DIY AAC ranges from low-tech solutions like handmade communication diaries and picture boards to…

DIY Accessibility(also: Do-It-Yourself Accessibility, Grassroots Accessibility)

An approach in which disabled people, their families, or proximate makers design and fabricate their own accessible artefacts—assistive tools, tactile labels, adapted clothing, switch-accessible toys—outside institutional assistive-technology supply chains, often using…

DIY Assistive Technology(also: DIY-AT, Do-It-Yourself Assistive Technology)

Assistive technology that is designed, fabricated, or modified by individuals, communities, or non-commercial entities rather than purchased from commercial manufacturers. DIY-AT often uses accessible fabrication methods like 3D printing to create customized, low-cost solutions…

DIY Assistive Technology(also: Do-It-Yourself Assistive Technology, Maker Assistive Technology)

DIY assistive technology refers to the practice of creating, modifying, or adapting assistive devices and tools through do-it-yourself methods, often using digital fabrication technologies such as 3D printers and laser cutters. This approach empowers people with disabilities,…

DIY assistive technology(also: DIY-AT, Maker assistive technology, Open-source AT)

Assistive devices and tools created or customised by end users, volunteers, or makers using accessible fabrication methods such as 3D printing, laser cutting, and off-the-shelf components. DIY-AT offers advantages over commercial assistive technology including lower cost,…

DIY-AT(also: Do-It-Yourself Assistive Technology, DIY Assistive Technology)

Assistive technology that is custom-made — often using digital fabrication, low-cost electronics, 3D printing, or everyday craft materials — by or with disabled people, their families, therapists, or community members, rather than purchased as a commercial product. DIY-AT…

DTMF(also: Dual-Tone Multi-Frequency, Touch-Tone)

DTMF (Dual-Tone Multi-Frequency) is the signaling system used when pressing keys on a telephone keypad, where each key press generates a unique combination of two audio frequencies. In accessibility contexts, DTMF input serves as an alternative interaction method for voice-based…

Daltonization(also: Recolouring, Color Remapping)

Daltonization is a computational technique that modifies the colours in an image or on a screen to make them more distinguishable for people with colour vision deficiency (CVD). Named after John Dalton, who first described his own colour blindness in the 18th century,…

Dasher

A zooming text entry interface in which users write by navigating through a world of nested boxes, each labeled with a letter and sized proportionally to its probability under a language model. Users control navigation using any pointing device, including eye trackers, mice, or…

Data Glove(also: digital glove, sensor glove, wired glove)

A wearable input device equipped with sensors to capture hand and finger movements, positions, and orientations. Data gloves use technologies like gyroscopes, accelerometers, flex sensors, or fiber optics to track hand gestures. In accessibility, data gloves enable sign language…

Data Minimization

A privacy principle requiring that organizations collect, process, and retain only the minimum amount of personal data necessary to accomplish a specific purpose. For assistive technology users, data minimization is particularly important because these technologies often capture…

Data Protection(also: Data Privacy)

The practices, policies, and legal frameworks governing how personal information is collected, stored, processed, and shared by organizations. For assistive technology companies, data protection is especially critical because their products often collect intimate details about…

Data sonification(also: Auditory graph, Audio chart)

The representation of data values through non-speech audio, typically by mapping numerical values to auditory parameters such as pitch, volume, duration, or timbre. Data sonification makes charts and graphs accessible to blind and low-vision users by allowing them to perceive…

Data-based Synthesis(also: Corpus-based Synthesis, Unit Selection Synthesis)

A speech synthesis technique that generates speech by selecting and concatenating segments from a large database of prerecorded human speech, rather than using rules to generate acoustic waveforms from scratch. The database is indexed with phoneme boundaries, pitch, and prosodic…

Data-to-Text(also: Data-to-Text Generation, Data-to-Text NLG)

A subfield of natural language generation (NLG) that automatically produces human-readable text from structured data, such as databases, spreadsheets, or sensor readings. Data-to-text systems analyze input data to identify patterns, trends, and salient features, then generate…

DataGlove(also: Data Glove, Sensor Glove, Cyber Glove)

A wearable input device fitted with sensors that captures hand shape, finger position, and hand orientation data in real time. Originally developed by VPL Research in the 1980s, DataGloves were used extensively in early virtual reality and sign language recognition research to…

Dead Reckoning(also: Inertial Navigation, Pedestrian Dead Reckoning, PDR)

Dead reckoning is a navigation technique that estimates a user's current position by tracking their movement from a known starting point, using data from inertial sensors such as accelerometers and gyroscopes. In accessible wayfinding applications for blind and low-vision users,…

Dead Time(also: Wait Time, Idle Time)

In scanning-based assistive technology interfaces, the period during which a user must passively wait before they can make their next input action. In row-column scanning, dead time occurs while waiting for the desired row or column to be highlighted. Longer dead times reduce…

Debounce(also: Debounce Filter, Key Debounce, Bounce Key Filter)

A keyboard accessibility feature that filters out unintended extra keypresses caused by tremor or imprecise motor control. When enabled, the system ignores rapid successive activations of the same key within a specified time window, treating them as a single press. Debounce is…

Decision Delay(also: Cognitive Delay, Selection Delay)

The time a user spends deciding whether to accept or reject a suggestion from a predictive system, such as a word prediction list on an assistive technology device or keyboard. Decision delay is a cognitive cost that can offset the motor efficiency gains of word prediction:…

Decision-Theoretic Planning(also: Decision-Theoretic Approach)

A computational approach to planning that uses mathematical models of decision-making under uncertainty, most commonly Markov Decision Processes (MDPs), to select optimal actions based on the current state of the system and predicted outcomes. In assistive technology,…

Deconvolution

A computational process that reverses the blurring effects of convolution in an optical or imaging system. In the context of visual accessibility, deconvolution is used to pre-process images displayed on a computer screen so that when viewed through an eye with known…

Defluffing(also: Content Defluffing, Clutter Removal)

The process of removing non-essential visual elements from a web page — such as banners, advertisements, decorative images, and sidebar content — to expose the core information content more directly to assistive technology users. In the context of web accessibility transcoding,…

Deformable Input(also: Flexible Input Surface)

An input method that uses physically flexible or pressure-sensitive surfaces that can be bent, squeezed, twisted, or otherwise deformed to generate control signals. Deformable input devices can provide accessible interaction for users with motor impairments, as they may require…

Depth Camera(also: Depth Sensor, RGB-D Camera, 3D Camera)

A depth camera is a device that captures both standard visual imagery and per-pixel distance information, producing a 3D representation of the scene. Technologies include structured light (projecting patterns and measuring distortion), time-of-flight (measuring how long light…

Depth Estimation(also: Monocular Depth Estimation, Depth Prediction)

The computer vision task of predicting the distance from the camera to each point in a scene, producing a depth map in which each pixel carries a distance value. Monocular depth estimation uses a single RGB image (no stereo cameras or LiDAR) and typically relies on deep learning…

Depth Sensing(also: Depth Perception (computer vision), 3D Sensing)

The ability of a sensor or system to measure the distance from itself to objects in the scene, producing a depth map or point cloud rather than a flat image. Common approaches include stereo vision (triangulating between two cameras), structured light (projecting a known…

Depth Sensor(also: Depth Camera, RGB-D Sensor, 3D Sensor)

A device that captures three-dimensional depth information about a scene in addition to standard two-dimensional imagery. Depth sensors measure the distance from the camera to objects in the environment, enabling more accurate detection and tracking of faces, hands, and body…

Descriptive Video Service(also: DVS, Described Video)

A service that provides audio descriptions of visual content in television programs, films, and other video media for blind and low-vision viewers. Originally developed by WGBH in Boston in the 1980s, DVS was one of the earliest systematic efforts to make visual media accessible…

Design Pattern(also: Interaction Pattern, Pattern of Assistive Interaction)

A reusable, generalised description of a solution to a commonly recurring design problem, expressed in a way that can be applied across different contexts without prescribing a specific implementation. In assistive technology design, interaction patterns describe the functional…

Developmental screening(also: Early developmental screening, Autism screening)

A brief, standardized assessment process used to identify infants and young children who may be at risk for developmental delays or disabilities, including autism spectrum disorder. Common screening instruments include the Checklist of Autism in Toddlers (CHAT), the Screening…

Device Abandonment(also: Technology Abandonment, AT Abandonment)

The phenomenon where users stop using an assistive technology device after initial adoption. In AAC, abandonment rates are notably high and stem from multiple factors including devices that do not match users' communication strengths, poor customization, high cost, social…

Device Customization(also: AT Customization, Personalization)

The process of modifying or tailoring an assistive device to meet the specific physical, cognitive, or sensory needs of an individual user. Customization can range from simple adjustments like resizing a grip to complete redesigns of a device. 3D printing has made customization…

Device Fit(also: AT Fit, Assistive Device Fit)

The degree to which an assistive technology device matches the physical, cognitive, and contextual needs of its user. Good device fit encompasses physical dimensions, grip requirements, material properties, weight, and alignment with the user environment and daily routines. Poor…

Device Switching(also: Device Transition, Cross-Device Interaction)

The process of moving between different computing devices to complete tasks, such as switching from a smartphone to a laptop or tablet. For people with motor impairments, particularly wheelchair users, device switching presents significant accessibility barriers because it often…

Dialog Act(also: Dialogue Act, Speech Act)

A classification label representing the communicative intention behind a spoken or written utterance in a conversational system. In the context of accessible technology, dialog acts are used to interpret what a user wants to accomplish when issuing voice commands — for example,…

Dialog Interface(also: Dialogue Interface, Conversational Interface)

A user interface paradigm in which interaction occurs through a structured exchange of prompts and responses, typically using speech or text. In assistive technology contexts, dialog interfaces present content and navigation options through audio prompts, allowing users to make…

Diarization(also: Speaker Diarization, Speaker Segmentation)

The process of automatically determining "who spoke when" in an audio or video recording by segmenting the audio stream and assigning each segment to a specific speaker. In accessibility contexts, diarization is critical for deaf and hard of hearing users who rely on captions or…

Dichoptic presentation(also: Dichoptic display, Dichoptic filtering, Dichoptic stimulation)

A technique in which different visual information is presented separately to each eye, typically using color-filtered glasses (red-cyan or red-green anaglyph), polarized lenses, or head-mounted displays. In clinical settings, dichoptic presentation is used as a therapeutic…

Digital Art Accessibility(also: Accessible Digital Art Tools)

The design and availability of digital creative tools—including drawing software, graphic input devices, and editing platforms—that can be effectively used by artists with disabilities. Key accessibility considerations include customizable pressure sensitivity, simplified menu…

Digital Assistive Technology(also: Digital AT, Software-Based AT)

Assistive technologies delivered through software, applications, and digital platforms rather than dedicated physical devices. Digital AT includes screen readers, speech-to-text tools, magnification software, communication apps, and AI-powered features embedded in smartphones,…

Digital Compass(also: Electronic Compass, Magnetometer)

An electronic sensor that detects the Earth's magnetic field to determine the direction a person or device is facing, providing heading information in degrees or cardinal directions. In assistive technology for blind and visually impaired users, digital compasses are integrated…

Digital Embroidery(also: Computerised Embroidery, Machine Embroidery)

Fabrication of stitched patterns on fabric using a computer-controlled embroidery machine that reads a digitised design file (e.g., DST, EXP) and drives a needle to produce precise, repeatable stitches. In accessibility work, digital embroidery is used to build tactile textile…

Digital Family Portrait

Digital Family Portrait is a 2001 research prototype from Georgia Institute of Technology (Mynatt et al.) that uses an ambient, picture-frame-style display in an adult child's home to represent the daily activity of an older relative living remotely. The portrait's decorative…

Digital Intervention(also: Digital Health Intervention, Technology-Based Intervention)

A health or behavioural support programme delivered through digital technology such as apps, games, or web platforms. Digital interventions for accessibility include cognitive training tools for people with ADHD, speech therapy apps, mental health chatbots, and gamified…

Digital Living Media(also: Living Media Interface, Biotic Design)

Systems that combine living organisms with electronic components as part of a digital interface. In accessibility contexts, digital living media have been explored as motivational tools for children with disabilities, where the growth of a living organism (such as a mushroom…

Digital Phenotyping(also: Active Digital Phenotyping, Passive Digital Phenotyping, Behavioral Phenotyping)

The use of data from digital devices (smartphones, computers, wearables) to quantify behavioral and physiological characteristics relevant to health or ability. Passive digital phenotyping collects data unobtrusively during natural device use (e.g., analyzing typing patterns or…

Digital Ruler(also: Reading Ruler, Line Guide)

A digital tool that constrains the visible area of text to specific lines or paragraphs, reducing visual crowding and helping readers maintain focus on the current reading position. Digital rulers are analogous to physical reading rulers or overlays used by people with dyslexia.…