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ASL Grammar(also: American Sign Language Grammar)

The linguistic rules governing the structure and use of American Sign Language, which differs fundamentally from English grammar. ASL has its own syntax, morphology, and phonology, with word order, spatial grammar, and non-manual markers playing central roles. NMS serve as…

ASL Linguistic Markers(also: Non-Manual Markers, Non-Manual Signals, ASL Facial Grammar)

Facial expressions, head movements, and body postures that serve grammatical and semantic functions in American Sign Language and other sign languages, distinct from emotional facial expressions. Common ASL linguistic markers include MM (meaning effortlessly or regularly,…

ASL education technology(also: Sign language learning technology)

Technology designed to support the teaching and learning of American Sign Language, ranging from video-based instructional platforms and feedback systems to computer vision tools that analyse signing performance. ASL education technology is an accessibility enabler because…

ASLTA(also: American Sign Language Teachers Association)

A US-based professional association founded to support and certify ASL educators. ASLTA publishes curriculum standards, offers certification at multiple levels (Provisional, Qualified, Professional, Master), runs professional development events, and advocates for rigorous ASL…

ASR Captioning(also: Automatic Captioning, Live Auto-Captioning, AI Captioning)

The use of automatic speech recognition (ASR) technology to generate real-time text captions of spoken language, commonly used as an accessibility tool for Deaf and Hard of Hearing individuals in meetings, lectures, and video calls. Unlike professional captioning services (such…

ASSETS(also: ACM SIGACCESS Conference on Computers and Accessibility)

The premier academic conference on accessible computing, organized by ACM SIGACCESS (Special Interest Group on Accessible Computing). ASSETS began as a research conference planned by SIGCAPH (the predecessor to SIGACCESS) in the early 1990s and has grown into the leading venue…

AT Abandonment(also: Assistive Technology Abandonment, Device Abandonment)

The discontinuation of use of an assistive technology device by its intended user. AT abandonment rates are significant, with research showing that up to one-third of all assistive devices are abandoned within the first year. Common reasons include poor device fit, lack of…

AT Impact Framework(also: ATIF, Assistive Technology Impact Framework)

A multi-level conceptual framework for evaluating the impact of assistive technology interventions on quality of life, developed from longitudinal research with smartphone users with sensory disabilities in Kenya. ATIF is structured across three ecological levels: Self…

AT Information Access(also: Assistive Technology Information Access)

The ability of people with disabilities, caregivers, professionals, and other stakeholders to find, understand, and use information about assistive technology products and services. Effective AT information access requires content that is available in relevant languages and…

AT Service Delivery(also: Assistive Technology Service Delivery)

The systems, processes, and organizational structures through which assistive technology devices and services reach end users. Effective AT service delivery encompasses needs assessment, device selection, fitting, training, follow-up, and ongoing support. Models range from…

ATAG(also: Authoring Tool Accessibility Guidelines)

A W3C standard that provides guidelines for making authoring tools—such as content management systems, HTML editors, and website builders—both accessible to authors with disabilities and capable of producing accessible content. ATAG 2.0, published in 2015, is organized into two…

ATK(also: Accessibility Toolkit, Linux Accessibility Toolkit, AT-SPI)

ATK (Accessibility Toolkit) is the accessibility framework for the Linux desktop environment, providing an API through which applications expose their user interface elements to assistive technologies such as the Orca screen reader. ATK defines interfaces for accessible objects…

ATutor

ATutor is an open-source web-based Learning Management System (LMS) developed at the University of Toronto's Adaptive Technology Resource Centre (ATRC, now the Inclusive Design Research Centre) with accessibility as a founding design principle. Created in the early 2000s to…

Abacus(also: Cranmer Abacus, Counting Frame)

A manual calculating tool consisting of a frame with rods and movable beads used for arithmetic operations. For visually impaired users, adapted versions like the Cranmer abacus feature beads that stay in place when moved and a backing to prevent displacement. The abacus enables…

Abandonment of Assistive Technology(also: Assistive Technology Abandonment, AT Abandonment, Assistive Technology Discontinuance)

Abandonment of assistive technology is the well-documented phenomenon in which a substantial proportion of assistive devices acquired by disabled users — commonly reported in the literature at roughly one-third or higher — end up unused or discarded within a few years of…

Ability Assumptions(also: Ability-Based Assumptions, Normative Assumptions)

Ability assumptions are the implicit expectations that technology designers build into systems about users' physical, sensory, and cognitive capabilities. These assumptions — about how fast someone moves, their range of motion, body proportions, grip strength, speech patterns,…

Ability Bias(also: Ability-Based Bias, Disability Bias)

A form of social bias encoded in artificial intelligence systems, particularly large language models, that reflects stereotypical or discriminatory assumptions about people with disabilities. Ability bias manifests through linguistic associations that link specific disabilities…

Ability Heuristics

A set of nine accessibility-focused design heuristics — Adaptability, Equitable Experience, Flexible Task Completion, Efficiency and Effectiveness of User Action, Multiple Modalities, Understandable Messages, Ease of Adoption, Ability Data Transparency, and Help, Support, and…

Ability Model(also: Ability-Based User Model)

A representation of a user that focuses on what they can do rather than demographic characteristics or disability categories. Unlike traditional user models that capture preferences, background, or impairment labels, ability models document the specific abilities a user has for…

Ability assumption in AI(also: Visual ability assumption, Sighted bias in AI)

The tendency of AI systems to assume users possess typical sensory, cognitive, or physical abilities, leading to inappropriate responses or instructions. In the context of visual AI assistants for blind users, ability assumptions manifest as the system asking users to "read the…

Ability requirement(also: Ability demand, Interaction prerequisite)

A capability that a person must possess in order to use a technology system, created implicitly by the system's design. AI systems generate new ability requirements: voice assistants require recognizable speech production, autonomous vehicles require pedestrians to look and move…

Ability-Based Design(also: ABD)

A design paradigm for accessible technology introduced by Jacob Wobbrock and colleagues that emphasizes adapting systems to meet users' abilities rather than requiring users to adapt to systems. Ability-based design applies "design-for-one" strategies universally, positioning…

Ability-Based Design(also: ABD)

A design philosophy that focuses on what users can do rather than what they cannot, adapting systems to leverage each individual's specific abilities. Instead of designing for a "typical" user and then adding accessibility accommodations, ability-based design starts from the…

Ability-Diverse Collaboration(also: Cross-Ability Collaboration, Mixed-Ability Collaboration)

A framework for understanding collaborative interactions between individuals with different abilities, where participants strategically combine and share their capabilities to achieve shared outcomes. The Ability-Diverse Collaboration Framework identifies two key modes of…

Ability-Mediating Design

A design framework introduced by Radu-Daniel Vatavu that focuses on how interactive systems mediate and reshape users' abilities rather than adapting to fixed abilities. Its core principles are mediation (systems empower users with enhanced skills), world coverage (systems…

Ability-based calibration(also: Adaptive calibration, Movement range calibration)

The process of adjusting a technology system's input sensitivity and thresholds to match an individual user's physical capabilities and range of motion, rather than assuming a normative body. In motion-based gaming and rehabilitation, ability-based calibration typically involves…

Ability-based design(also: ABD)

An accessibility framework that shifts the design focus from disability (what users cannot do) to ability (what users can do), arguing that interactive systems should adapt to users' actual capabilities rather than requiring users to conform to standard interfaces. Proposed by…

Ablation Study(also: Ablation Experiment)

A methodology, common in machine-learning and systems research, in which individual components of a system are systematically removed or disabled to measure their contribution to overall performance. In accessibility testing research, ablation studies are used to justify design…

Ableism(also: Disability discrimination, Disablism)

Discrimination, prejudice, or social bias against people with disabilities, rooted in the assumption that typical abilities are superior and that disabled people need to be fixed or are inherently less capable. Ableism operates at multiple levels: structural (inaccessible…

Ableist Language(also: Disability Slurs, Derogatory Disability Language)

Ableist language refers to words, phrases, and framings that demean, stereotype, or pathologize people with disabilities — from explicit slurs such as 'cripple,' 'handicap,' 'retard,' or 'lame' used pejoratively, to subtler framings like 'suffers from,' 'wheelchair-bound,' or…

Ableist Microaggressions Scale(also: AMS)

A validated measurement instrument developed by Conover, Israel, and Nylund-Gibson (2017) to systematically assess the frequency and impact of subtle, everyday expressions of ableism. The AMS organises disability microaggressions into four empirically supported domains —…

Ableist microaggression(also: Disability microaggression, Casual ableism)

A subtle, often unintentional comment, question, or behavior that communicates hostile, derogatory, or negative assumptions about disability. Examples include unsolicited compliments on "bravery" for performing routine tasks, expressions of surprise at a disabled person's…

Above the Fold(also: Above-the-fold, First Screen Content)

Content that is visible on a web page without requiring the user to scroll. The term originates from newspaper publishing where important headlines appeared above the physical fold of the paper. In digital accessibility and usability, above-the-fold placement is significant…

Abstract Syntax Tree(also: AST, Syntax Tree)

A hierarchical tree representation of source code structure that captures the syntactic relationships between programming constructs like functions, classes, loops, and statements. In accessibility, AST-based navigation tools like StructJumper allow blind programmers to traverse…

Abstract Widget(also: Abstract Interaction Object)

A user interface component defined by its semantic purpose and interaction behavior rather than its visual appearance. Abstract widgets specify what a user can do (select from options, enter text, trigger a command) without prescribing how the interaction is rendered — it could…

Abundant Design(also: Abundant UI Design)

A design approach for cognitively accessible interfaces in which primary actions are represented by multiple redundant cues — short text, an icon, a distinctive color, and ample size — so users can identify the control through whichever channel suits them. Contrasts with minimal…

Academic Ableism

Systemic discrimination against disabled people within academic institutions and research practices. In higher education, academic ableism manifests through inaccessible learning environments, expectations of productivity that do not account for disability, and research…

Academic Accessibility(also: Accessibility in academia, Scholarly accessibility)

The degree to which the tools, publications, venues, and institutional practices of academic research and higher education are usable by disabled students, faculty, and researchers. Academic accessibility spans scholarly PDFs and figures, reference and qualitative-analysis…

Academic Accommodation(also: Educational Accommodation, Reasonable Adjustment in Education)

Modifications to academic requirements, procedures, or environments that enable students and scholars with disabilities to participate equally in educational activities. Academic accommodations may include extended time for exams, alternative format materials, note-taking…

Academic Accommodations(also: Educational Accommodations, Disability Accommodations)

Modifications to academic requirements, environments, or procedures provided to students with disabilities to ensure equal access to education. Common accommodations include extended test time, note-taking services, priority seating, alternative format materials, and reduced…

Accelerated Speech(also: Time-Compressed Speech, Speed-Up Speech)

Audio output played at faster than normal speaking rate, commonly used by people with visual impairments when interacting with screen readers and other audio-based assistive technologies. Research shows that experienced screen reader users can comprehend speech at up to 500…

Accelerometer

A sensor that measures acceleration forces, including the constant force of gravity, along one or more axes. Accelerometers in smartphones and wearable devices detect device orientation, movement, and gestures. In accessibility applications, accelerometer data enables…

Acceptance Testing(also: User Acceptance Testing, UAT, Acceptance Tests)

A form of software testing that validates whether a system meets its specified requirements from the end user's perspective. In accessibility, acceptance tests simulate real user interaction scenarios — such as navigating a web page using only the keyboard or activating…

Acceptance and Commitment Therapy(also: ACT)

A form of cognitive behavioral therapy that encourages acceptance of unwanted thoughts and feelings rather than fighting or suppressing them, combined with commitment to actions aligned with personal values. For OCD, ACT teaches individuals to acknowledge obsessive thoughts…

Access Barrier(also: Accessibility Barrier, Barrier to Access)

Any obstacle that prevents or diminishes a disabled person's ability to complete a task, participate in an activity, or access information. Access barriers are not limited to complete inability (failure points) but also include situations where tasks can be completed but with…

Access Barriers(also: Barriers to Access)

Obstacles that prevent or impede disabled people from fully participating in activities, accessing services, or using technologies. Access barriers can be physical (inaccessible buildings), digital (websites without screen reader support), attitudinal (employer discrimination),…

Access Conflict(also: Accessibility Conflict, Competing Access Needs)

A situation in which the accessibility requirements of one person conflict with or undermine the accessibility requirements of another person. For example, a student prone to migraines may need low lighting in a classroom, while a student with low vision requires bright, direct…

Access Differential(also: Accessibility Gap, Access Gap)

Access differential is the gap between the access that nondisabled people experience and the access that people with disabilities experience when using the same technologies, services, or environments. Unlike a binary view of accessibility (accessible or not), access…

Access For All(also: ISO/IEC 24751, IMS Access For All, AfA)

An international standard (ISO/IEC 24751) for describing user accessibility needs and preferences in a portable, application-independent format. Originally developed by the IMS Global Learning Consortium for educational contexts, it was adopted as an ISO standard and uses XML…

Access Friction(also: Accessibility Friction)

The effort, frustration, or barriers encountered when attempting to access technology, services, or environments. Access friction can range from minor inconveniences to complete exclusion and may result from poorly designed interfaces, lack of accommodations, bureaucratic…