Glossary

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Visual guidance(also: Visual cueing, Visual highlighting)

Assistive techniques that direct a user's visual attention to relevant content through highlights, outlines, magnification, or other visual cues. For people with low vision, visual guidance systems can compensate for reduced visual acuity or restricted visual fields by making…

Visual processing(also: Visual perception, Visual cognition)

The brain's ability to interpret, organise, and make sense of visual information received from the eyes, involving multiple neural pathways including the ventral stream (object recognition, "what" pathway) and the dorsal stream (spatial awareness and motion, "where" pathway).…

Visual question answering(also: VQA, Visual QA)

A computer vision and natural language processing task in which a system answers natural language questions about the content of an image or video. In accessibility contexts, VQA enables blind and visually impaired users to query visual content interactively — asking specific…

Visual search

The perceptual task of scanning a visual scene to locate a specific target among distractors. Visual search is significantly affected by low vision, visual field loss, and other visual impairments, as reduced acuity or restricted fields make it harder and slower to locate…

Visual substitution(also: Sensory substitution, Vision substitution)

Visual substitution is a design strategy in assistive technology that replaces visual information with output in another sensory modality, such as audio descriptions, haptic feedback, or tactile representations. It contrasts with visual enhancement, which amplifies or augments…

Visual-Inertial Odometry(also: VIO)

A computer vision technique that combines camera imagery with motion sensor data (accelerometer and gyroscope) to track a device's position and orientation in 3D space. In accessibility applications, VIO enables smartphones to maintain awareness of object positions even when…

Visual-Motor Integration(also: Visuomotor Integration, VMI, Eye-Hand Integration)

The coordination of visual perception with motor output, enabling activities like writing, drawing, catching a ball, or manipulating objects based on visual information. Visual-motor integration is commonly assessed using standardized tests like the Beery-Buktenica VMI in…

Visual-Spatial Processing(also: Visuospatial Processing, Visual-Spatial Cognition)

Visual-spatial processing is the cognitive ability to perceive, analyze, and mentally manipulate spatial relationships and visual information. It encompasses skills such as judging distances, understanding maps, recognizing shapes and patterns, and mentally rotating objects.…

Visual-Syntactic Text Formatting(also: VSTF)

Visual-Syntactic Text Formatting (VSTF) is a content presentation method that formats text based on its syntactic structure, using indentation, line breaks, and visual grouping to align with the grammatical structure of sentences. Research has shown VSTF can improve online…

Visualization Literacy(also: Data Visualization Literacy, Graphical Literacy, Graph Literacy)

The ability to read, interpret, and extract meaningful insights from visual data representations such as charts, graphs, maps, and infographics. Visualization literacy encompasses skills like identifying trends, making comparisons, understanding scales and axes, and critically…

Visualization Question Answering(also: Chart QA, Visualization QA, VisQA)

A class of interactive systems that let users ask natural-language questions about a data visualization — a chart, graph, or map — and receive direct textual or spoken answers rather than having to interpret the visualization themselves. Visualization QA systems typically…

Visually Impaired(also: Vision Impairment, Visual Impairment, BVI)

An umbrella term for any degree of reduced visual function that cannot be fully corrected with standard glasses or contact lenses, ranging from mild low vision to total blindness. The term is frequently combined as BVI (blind and visually impaired) in accessibility research to…

Visuocentric Design(also: Visual-First Design, Deaf-Centric Design)

An approach to interface and content design that prioritizes visual communication and spatial organization, particularly for users of visual languages like sign languages. Visuocentric design recognizes that deaf and hard of hearing users process information visually rather than…

Visuospatial Attention(also: Visual-Spatial Attention, Visuospatial Processing)

The cognitive ability to attend to, process, and mentally manipulate visual and spatial information in the environment. Visuospatial attention involves orienting to locations in space, tracking objects, and understanding spatial relationships between elements. Research has…

Viterbi Algorithm

The Viterbi algorithm is a dynamic-programming procedure for finding the most likely sequence of hidden states in a Hidden Markov Model given a sequence of observations. It is the standard solution to part-of-speech tagging, many speech-recognition tasks, and decoding problems…

Vitiligo

A chronic skin condition in which patches of skin lose their pigment, resulting in irregular white or light areas on the body. Vitiligo can affect people of any skin tone but is more visually apparent on darker skin. The World Health Organization includes vitiligo under the…

VizWiz

A mobile application and research platform that allows blind people to take photos with their phones and receive answers to visual questions from human workers or AI systems. VizWiz originated as a research project at Carnegie Mellon University and has generated important…

Vlog(also: Video Blog, Video Blogging, Vlogging)

A video-based form of blogging where individuals create and share content through recorded video rather than written text. For Deaf communities, vlogging has become a particularly important communication medium because it enables expression in sign language, bypassing the…

Vocal Development(also: Speech Development, Vocal Production Development)

The process by which individuals acquire and refine the ability to produce speech sounds and vocalizations. In typically developing children, vocal development progresses through stages from cooing and babbling to first words and complex speech. For children with autism spectrum…

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…

Vocal Programming(also: Voice Coding, Speech-Based Programming, Voice Programming)

The practice of writing, editing, and navigating computer code using speech recognition rather than keyboard input. Vocal programming is an important accessibility concern because conventional software development tools implicitly require the use of a keyboard, creating a…

Vocal Source Identity

Vocal Source Identity is an auditory display principle referring to the use of different speaking voices or sound sources to convey distinct types of information in an audio interface. In the context of non-visual web browsing, different synthesised voices might represent…

Vocal Stereotypy(also: Vocal Stereotypies, Vocal Stim)

Repetitive, non-functional vocalizations that serve no apparent communicative purpose, commonly observed in individuals with autism spectrum disorder and other developmental disabilities. Vocal stereotypies may include repetitive humming, squealing, echolalia (repeating heard…

Vocalization Analysis(also: Vocal Analysis, Infant Vocalization Analysis)

Vocalization analysis is the systematic study and measurement of vocal productions, including speech, pre-speech sounds, and non-speech vocalizations. In developmental and clinical contexts, vocalization analysis involves recording, digitizing, and examining acoustic features of…

Vocational Inclusion(also: Employment Inclusion, Labor Market Inclusion)

The meaningful participation of people with disabilities in the labor market, encompassing not just job placement but access to professional development, training, career advancement, and equitable working conditions. Despite international policy frameworks like the UNCRPD and…

Vocational Rehabilitation(also: VR, Employment Rehabilitation)

Services and programs designed to help people with disabilities prepare for, obtain, maintain, or return to employment. Vocational rehabilitation may include assessment, counseling, training, job placement, assistive technology provision, workplace modification, and ongoing…

Vocational Training(also: Vocational Education, Job Training, Occupational Training)

Vocational training is education focused on developing practical skills and knowledge required for specific occupations or trades. In accessibility contexts, vocational training for people with disabilities is a critical pathway to economic independence and social inclusion, yet…

Voice Acting(also: Voice Performance, Character Voicing)

The performance art of providing voices for characters, narration, and other spoken content in media such as animation, audiobooks, games, and audio-described content. In accessible media production, voice acting significantly impacts emotional engagement and…

Voice Activity Detection(also: VAD, Speech Detection)

A signal processing technique that automatically determines whether a segment of audio contains human speech or not. In accessibility applications, voice activity detection is used in audio description timing systems to identify non-speech segments where descriptions can be…

Voice Assistant(also: Virtual Assistant, Smart Speaker)

An AI-powered system that responds to voice commands to perform tasks, answer questions, and control devices, such as Amazon Alexa, Google Assistant, and Apple Siri. Voice assistants have accessibility potential for people with vision impairments by providing hands-free,…

Voice Assistant(also: Smart Speaker, Voice-Activated Assistant, Conversational Agent)

A software application that uses speech recognition and natural language processing to respond to voice commands and perform tasks. Common examples include Amazon Alexa, Google Assistant, and Apple Siri. Voice assistants offer accessibility benefits for users who have difficulty…

Voice Augmentation(also: Audio Augmentation, Voice-Based Augmentation)

A technique for enhancing user interfaces by adding spoken audio feedback to supplement visual information on screen. Voice augmentation provides contextual support through spoken confirmations of user input, notifications of errors or status changes, suggestions for next…

Voice Browser(also: Voice Web Browser, Audio Browser)

A voice browser is a type of web browser that presents web content through speech output and accepts voice or keyboard input rather than relying on visual display. Voice browsers convert web page content to synthesized speech using text-to-speech technology, allowing users who…

Voice Cloning(also: Voice Synthesis Cloning, Personalized Text-to-Speech)

The use of machine-learning models to synthesise a target speaker's voice from a short reference recording, enabling text-to-speech output that sounds like that specific person. For accessibility, voice cloning has transformative potential: people whose voices are at risk of…

Voice Command(also: Voice Control, Spoken Command)

An input method where users speak predefined words or phrases to control software or perform actions. In assistive technology, voice commands enable hands-free and eyes-free interaction, allowing users to perform operations like text editing (delete, insert, replace),…

Voice Control(also: Voice Command, Voice-Activated Control)

The ability to operate devices, applications, or systems using spoken commands. Voice control is a key accessibility feature in smart home technology, enabling people with mobility impairments, visual disabilities, or dexterity limitations to independently control their…

Voice Conversion(also: VC, speech conversion)

A speech processing technique that transforms one person's voice to sound like another while preserving the linguistic content. In accessibility applications, voice conversion can improve the intelligibility of speech from people with articulation disorders by replacing unclear…

Voice Customization(also: Voice Personalization, Custom Voice)

The process of creating or modifying synthetic voices to match a user's preferences or identity, including attributes such as gender, age, pitch, breathiness, hoarseness, and speech variation. Voice customization is particularly important in accessibility for people with speech…

Voice Disabilities(also: Voice Disorders, Speech Impairment, Aphonia)

Conditions that partially or completely impair a person's ability to produce speech using their natural voice. Voice disabilities range from mild hoarseness or reduced volume to complete inability to vocalise (aphonia). Causes include laryngeal conditions, neurological disorders…

Voice Input(also: Voice Control, Voice Command, Speech Input)

An input modality that allows users to control devices, enter text, or issue commands using spoken language, typically processed through speech recognition technology. Voice input is an essential accessibility feature for people who cannot use traditional input devices such as…

Voice Interaction(also: Voice User Interface, VUI, Voice-Based Interaction)

An interaction paradigm where users communicate with technology primarily through spoken commands and receive audio responses, rather than using visual displays, keyboards, or touch screens. Voice interaction combines speech-to-text for input, natural language processing for…

Voice Interface(also: Voice User Interface, VUI)

A user interface that accepts spoken language as input and typically provides audio output, enabling hands-free, eyes-free interaction with technology. Voice interfaces are used in voice-activated personal assistants, smart speakers, phone systems, and accessibility tools. For…

Voice Interface(also: Speech Interface, Voice User Interface, VUI)

An interface that allows users to interact with a system using spoken natural language commands rather than keyboard, mouse, or touch input. Voice interfaces range from simple command-and-control systems that recognise fixed phrases to conversational assistants that interpret…

Voice Output Communication Aid(also: VOCA, Speech Output Device)

An electronic augmentative and alternative communication (AAC) device that produces synthesized or digitized speech output when a user selects symbols, words, or phrases. VOCAs range from simple single-message devices to sophisticated systems with extensive vocabularies and…

Voice Recognition(also: Speech Recognition, Voice Control, Voice Input)

Technology that identifies and processes human speech to convert it into text or execute commands. Voice recognition serves as a critical assistive technology for people with motor disabilities who cannot use a keyboard or mouse, enabling them to navigate websites, dictate text,…

Voice Usability(also: Auditory Usability, Non-Visual Web Usability)

The degree to which a web page, application, or document is usable when accessed through a voice browser or screen reader — the audio-first counterpart to traditional visual usability. Voice usability combines structural quality (navigability — how quickly a user can reach…

Voice User Interface(also: VUI)

A user interface that enables interaction with a device or system through spoken voice commands and audio responses. Voice user interfaces use speech recognition to interpret user input and text-to-speech or pre-recorded audio for output. For accessibility, VUIs provide an…

Voice User Interface(also: VUI, Voice Command Interface, Voice Interface)

An interface that allows users to interact with a device or application through spoken language commands rather than touch, mouse, or keyboard input. Voice user interfaces use automated speech recognition (ASR) to convert speech to text and natural language understanding (NLU)…

Voice Vista

A free audio-based navigation application for blind and low-vision users that uses 3D spatial audio to announce nearby streets, intersections, points of interest, and set beacons as the user walks. Voice Vista is a community-maintained successor to Microsoft Soundscape, released…

Voice and Video-Capable Language Model(also: VVLM, Multimodal AI Assistant, Video-Capable LLM)

A large language model that can process real-time or near-real-time video and audio input alongside text, enabling conversational interaction about the visual world. VVLMs represent a shift from static image analysis (single photo question-answering) to dynamic, continuous…