Glossary

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Inverse Kinematics(also: IK)

A mathematical technique used in computer animation and robotics to calculate the joint positions needed to place an end effector (such as a hand or foot) at a desired position in space. In signing avatar applications, inverse kinematics allows natural arm and body posture to be…

Invisible Cost of Disability(also: Hidden Cost of Disability, Disability Tax, Crip Tax)

The additional time, energy, money, and cognitive effort that people with disabilities must expend to accomplish tasks that non-disabled people can complete without such overhead. In workplace contexts, these costs include purchasing extra assistive technology and software,…

Invisible Disability(also: Hidden Disability, Non-Apparent Disability)

A disability that is not immediately apparent to others through visual observation. Invisible disabilities include ADHD, chronic pain, mental health conditions, learning disabilities, autoimmune conditions, traumatic brain injury, and many others. People with invisible…

Invisible Work(also: Invisible Labour, Hidden Work)

The unrecognized and often uncompensated effort that people with disabilities must perform to navigate inaccessible environments, technologies, and workplaces. In professional settings, invisible work includes learning workarounds for inaccessible software, preparing extensively…

Invisible disability(also: Hidden disability, Non-visible disability, Non-apparent disability)

A disability that is not immediately apparent to others by observation, including conditions such as chronic pain, ADHD, autism, anxiety, depression, epilepsy, and many cognitive or neurological conditions. People with invisible disabilities often face unique challenges around…

Invisible labor(also: Access labor, Hidden work)

The additional, often unrecognized effort that people with disabilities must invest to create and maintain access in environments not designed for them. In workplace contexts, invisible labor includes learning complex workarounds for inaccessible software, memorizing keyboard…

Irish Sign Language(also: ISL, Teanga Chomharthaíochta na hÉireann)

The indigenous sign language of the Deaf community in Ireland, distinct from both English and Irish (Gaelic) spoken languages and from British Sign Language (BSL). Like all sign languages, ISL uses manual features (hand shapes, movements, and positions) and non-manual features…

Ishihara Test(also: Ishihara Colour Test, Ishihara Plates)

A widely used clinical screening test for red-green colour vision deficiencies, consisting of a series of circular plates made up of coloured dots arranged in a mosaic pattern. Each plate contains a number or shape formed by dots of certain colours set against a background of…

Isolated Sign Language Recognition(also: isolated SLR, word-level sign recognition)

A sign language recognition task that focuses on identifying individual, pre-segmented signs rather than continuous signing sequences. In isolated SLR, each sign is captured as a separate video clip with clear start and end points, simplifying the recognition problem compared to…

Isolated Sign Recognition(also: ISR, ISLR)

A computer vision and machine learning task focused on identifying individual signs from video recordings where each video contains a single sign production, as opposed to continuous sign language recognition which processes connected signing in sentences or conversation.…

Isometric Gesture(also: Isometric Contraction Gesture)

An isometric gesture is a gesture in which a person activates their muscles without producing visible movement — the body position remains static while muscle tension changes. This contrasts with isotonic gestures, where visible hand or arm movement occurs over time. Isometric…

Isotonic Joystick(also: Displacement Joystick, Free-Moving Joystick)

An isotonic joystick is a type of joystick input device that moves freely in response to applied force and returns to a centre position when released. Unlike isometric (force-sensing) joysticks that remain stationary and measure the pressure applied, isotonic joysticks…

Italic Font Style(also: italics, oblique)

A slanted or cursive-style variant of a typeface, traditionally used for emphasis, titles, or foreign words. Eye-tracking research demonstrates that italic fonts create significant accessibility barriers—Arial Italic, for example, showed the worst reading performance across…

Iterative Crowdsourcing(also: Iterative Human Computation, Multi-Round Crowdsourcing)

A human computation workflow in which multiple rounds of crowd workers build iteratively upon each other's responses to collectively achieve higher quality results than any individual worker could produce alone. In each iteration, workers are shown the previous round's outputs…

Iterative Design(also: Iterative Development, Design Iteration)

Iterative design is a methodology where designs are developed through repeated cycles of prototyping, testing, analyzing, and refining. Each iteration incorporates feedback from evaluation to improve the design progressively. In accessibility work, iterative design is…

Itinerant Teacher(also: Traveling Teacher, Itinerant TVI)

A special education teacher who travels between multiple schools to provide services to students with disabilities, rather than being based at a single location. In the context of visual impairment services, itinerant TVIs (Teachers of students with Visual Impairments) typically…

JAWS(also: Job Access With Speech)

A commercial screen reader for Windows developed by Freedom Scientific (now part of Vispero). JAWS is one of the most widely used screen readers in professional and enterprise settings, providing text-to-speech and braille output for blind and low-vision users. It supports web…

JAWS for Windows(also: JFW)

JAWS (Job Access With Speech) for Windows is a commercial screen reader from Freedom Scientific (now Vispero) that provides speech and braille output for blind and low-vision users on the Windows operating system. The JFW mailing list and user group (jfw.groups.io) is one of the…

JIS X 8341-3(also: JIS X 8341, Japanese Industrial Standard for Web Accessibility)

JIS X 8341-3 is the Japanese Industrial Standard for web content accessibility, first published in 2004 by the Japanese Standards Association. The standard was developed with attention to harmonization with WCAG 1.0 and subsequently updated to align with WCAG 2.0. JIS X 8341-3…

JSML(also: Java Speech Markup Language)

An XML-based markup language developed by Sun Microsystems that provides directives for controlling the output of speech synthesis engines. JSML allows developers to specify pronunciation details including speaking rate, volume, pitch, emphasis, pauses, gender of synthetic…

Jailbreak(also: LLM Jailbreak, AI Jailbreak)

In the context of generative AI, a class of adversarial input designed to bypass a model's safety rules, instruction-following constraints, or content policy — for example, instructions that tell the model to "ignore previous rules" or role-play as an unrestricted assistant.…

Jakob's Law(also: Jakobs Law, Law of Familiarity)

A usability heuristic coined by Jakob Nielsen stating that users spend most of their time on other sites and expect your site to work like the ones they already know. Accessibility implication: novel interaction patterns impose higher cognitive load than familiar ones, so…

Japanese Sign Language(also: JSL, Nihon Shuwa)

The primary sign language used by the Deaf community in Japan. Japanese Sign Language (JSL) is a distinct natural language with its own grammar, vocabulary, and syntax that differs significantly from spoken Japanese. JSL uses spatial relationships rather than particles to…

Jenga Format

Jenga format is a content transformation technique designed to enhance web page readability for non-native English readers. Developed by Chen-Hsiang Yu and Robert C. Miller at MIT, it restructures text presentation by visually grouping syntactic units within sentences, making…

Jitter and Shimmer(also: Voice perturbation measures, Cycle-to-cycle variability)

Acoustic measures of voice quality that capture short-term irregularity in the vocal fold vibration. Jitter is the cycle-to-cycle variability in pitch (fundamental frequency), while shimmer is the cycle-to-cycle variability in amplitude. Elevated jitter and shimmer are…

Job Accommodation Network(also: JAN)

A free service funded by the U.S. Department of Labor's Office of Disability Employment Policy that provides guidance on workplace accommodations and disability employment issues. JAN offers one-on-one consultation to employers, employees, and service providers on practical…

Job Coach(also: Employment Specialist, Vocational Coach, Work Coach)

A professional who provides on-site support and training to help people with disabilities succeed in competitive employment settings. Job coaches assist with learning job tasks, developing workplace social skills, understanding employer expectations, and problem-solving…

Job Coaching(also: Employment Coaching, Workplace Coaching)

Individualized, on-site or remote support provided to workers with disabilities to help them learn job tasks, develop workplace skills, navigate social interactions, and maintain employment. Job coaches may provide direct training, model tasks, facilitate communication with…

Joint Attention(also: Shared Attention)

The shared focus of two or more individuals on the same object or event, typically involving one person directing another's attention through gaze, gesture, or verbal cues. Joint attention is a foundational social-cognitive skill that develops in early childhood and is often…

Joint Awareness

Joint awareness is a shared understanding between two or more people about a condition, situation, or state - for example, a child's sensory triggers known to both the child and their parent, or a chronic illness state visible to a patient and their caregiver. It contrasts with…

Joint Bilingual Navigation(also: Bilingual Form Navigation, Dual-Language Navigation)

An interface design approach that allows users to interact with digital content simultaneously in two languages through different modalities. In the context of Deaf accessibility, joint bilingual navigation enables a form or document to be navigated either through sign language…

Joint Hypermobility(also: Hypermobility, Double-Jointed)

A condition in which joints move beyond their normal range of motion, often associated with connective tissue disorders like Ehlers-Danlos Syndrome. Joint hypermobility can cause chronic pain, frequent dislocations, and difficulty with tasks requiring grip strength or sustained…

Joint attention(also: Shared attention)

The shared focus of two or more individuals on the same object or event, typically established through gaze, pointing, or other communicative cues. Joint attention is a foundational social-cognitive skill that develops in early childhood and is often impaired in individuals with…

Journaling(also: Diary Writing, Reflective Writing)

The regular practice of recording personal thoughts, feelings, and experiences in written, spoken, visual, or musical form. Journaling has documented benefits for mental health, emotion regulation, self-insight, and identity construction, and is widely used in therapy,…

Journey Mapping(also: Journey Map)

A qualitative research and design method in which participants describe a trip, task, or experience step-by-step across sequential phases (e.g., pre-trip, in-trip, post-trip), identifying the tools they used, the cues they relied on, the decisions they made, and the points where…

Joystick(also: Adaptive Joystick)

A joystick is an input device with a lever that tilts in multiple directions to control cursor movement on screen, used as an alternative pointing device by people with motor impairments who have difficulty using a standard mouse. Adaptive joysticks come in various forms — some…

Joystick Locomotion(also: Continuous Locomotion, Thumbstick Locomotion)

A VR locomotion method where users tilt a joystick or thumbstick on a controller to move continuously through the virtual environment while remaining physically stationary. This method is accessible for users who cannot physically walk but have sufficient hand motor control to…

Just-Noticeable Difference(also: JND, Difference Threshold, Differential Threshold)

The smallest detectable difference between two stimuli that a person can perceive. In accessibility contexts, JND is commonly applied to color, contrast, and audio levels—determining the minimum change needed for users to distinguish between two values. For color vision, JND…

Just-in-Time Intervention(also: JITI, Just-in-Time Adaptive Intervention, JITAI)

A technology-delivered intervention that provides the right type and amount of support at the right time, adapting to the user's current context, mental state, and needs. Unlike scheduled therapy sessions, just-in-time interventions use sensing technologies (smartphones,…

Just-in-Time Programming(also: JIT Programming, Real-Time AAC Configuration)

A method of configuring AAC devices in real time by capturing an image of a current activity, social interaction, or object and immediately creating a visual scene display with relevant communication options. Just-in-time programming enables communication partners to take…

Just-in-Time Prompting(also: Trigger-Based Prompting, On-Demand Visual Check)

A prompting technique for voice and video-capable AI models where the user pre-configures the AI with a role and task description, then uses a trigger phrase (such as "check now") to initiate an on-demand visual analysis of the current camera view. Developed as a workaround for…

Just-in-Time Support(also: JIT Support, Just-in-Time Programming, JIT Vocabulary)

In augmentative and alternative communication, the programming and availability of language concepts at the moment they are needed, rather than requiring pre-planning. Just-in-time support can be mentor-generated (e.g., a conversation partner quickly creating a hotspot on a…

K-12 Education(also: K-12, Primary and Secondary Education, K through 12)

The span of publicly supported education from kindergarten through 12th grade (approximately ages 5-18), encompassing primary and secondary schooling. In accessibility contexts, K-12 education is a critical focus area because accessible learning tools, curricula, and teacher…

K-Shot Learning(also: N-Way K-Shot Learning)

A machine learning paradigm where a model must learn to classify objects using only k training examples per class. In the context of accessibility, k-shot learning is significant because it enables assistive technologies like personal object recognizers to be trained with…

KWCAG(also: Korean Web Content Accessibility Guidelines)

The Korean national standard for web content accessibility, first published as KWCAG 1.0 in 2004 by the Telecommunications Technology Association (TTA). Modelled after WCAG, KWCAG adapts international accessibility guidelines to Korean web culture and technical circumstances.…

Kanji(also: Han Characters (in Japanese))

Logographic characters of Chinese origin used in the Japanese writing system alongside the two syllabic scripts, hiragana and katakana. Modern Japanese uses about 2,000-3,000 commonly-occurring kanji, but the full character set exceeds 10,000 glyphs, and historical or literary…

Kenyan Sign Language(also: KSL)

The primary sign language used by the deaf community in Kenya, recognized as a national language in Kenya's 2010 Constitution. KSL has its own grammar, syntax, and vocabulary distinct from spoken Kiswahili and English. In accessibility contexts, KSL is significant because many…

Keratoconus

A progressive eye condition in which the normally round cornea thins and bulges into a cone-like shape, causing irregular astigmatism and significant visual distortion that cannot be fully corrected with standard glasses or contact lenses. Keratoconus typically begins in…

Key Acceptance Delay(also: Acceptance Delay, Key Debounce)

A keyboard accessibility setting that requires a key to be held down for a specified minimum duration before it is registered as a deliberate press. Keys released before the delay period expires are ignored, filtering out brief accidental touches. Key acceptance delay is the…

Key Frame Extraction(also: Keyframe Selection, Key Frame Selection)

A computer vision technique that automatically identifies and selects the most representative or highest-quality frames from a continuous video stream. In accessibility contexts, key frame extraction is used in mobile assistive applications to select well-focused,…