Glossary

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TTY(also: TDD, Telecommunications Device for the Deaf, Text Telephone)

A text-based telecommunications device that enables people who are deaf, hard of hearing, or have speech disabilities to communicate over telephone lines by typing messages that are displayed on a screen or printed on paper. TTY devices were the primary means of telephone…

TTY Relay Service(also: Telecommunications Relay Service, TRS, Text Telephone Relay)

A telecommunications service that enables people who are deaf, hard of hearing, or have speech disabilities to communicate by telephone through a relay operator who converts between text and voice. Users type messages on a TTY (teletypewriter) device, and the relay operator…

Talking Mats

A visual communication framework that uses a textured mat and sets of picture symbols to help people express their views on topics that matter to them. Developed at the University of Stirling, Talking Mats provides a structured way for people who find it difficult to communicate…

Technical Agency

Technical agency, in the context of augmentative and alternative communication (AAC), refers to an individual's ability to actively participate in and contribute to a conversation through direct actions such as speaking, gesturing, or vocalizing. It is distinguished from…

Teleconferencing Accessibility(also: Video Conferencing Accessibility, Remote Meeting Accessibility)

The practice of ensuring that teleconference and video conferencing platforms and meetings are usable by people with disabilities, including deaf and hard of hearing users, blind and low-vision users, and people with cognitive or motor disabilities. Teleconferencing…

Telegraphic Speech(also: Telegraphic Input, Compressed Speech)

A simplified form of communication that uses only essential content words (nouns, verbs, adjectives) while omitting function words (articles, prepositions, conjunctions) and grammatical inflections. In AAC and assistive technology contexts, telegraphic input allows users with…

Text Gloss(also: Text Glosses)

In Augmentative and Alternative Communication (AAC), a text label or annotation associated with a visual symbol (such as an icon or pictogram) on a communication device. The text gloss serves two purposes: it provides a written description to help communication partners…

Text Messaging(also: SMS, Short Message Service, Texting)

Text messaging is the exchange of short written messages between mobile devices over a cellular or data network, most commonly using the SMS (Short Message Service) or MMS (Multimedia Messaging Service) standards, or modern over-the-top messaging apps. Text messaging has been a…

Text-to-Speech(also: TTS, Speech Synthesis, Screen Reading)

Technology that converts written text into spoken audio output, using either pre-recorded speech segments or synthesized voices. Text-to-speech is a foundational accessibility technology used by screen readers for blind users, by people with learning disabilities like dyslexia,…

Tone indicator(also: Tone tag)

A text-based marker appended to online messages to explicitly signal the intended emotional tone or communicative intent, such as /s for sarcasm, /j for joking, /gen for genuine, or /srs for serious. Tone indicators emerged from neurodivergent online communities to address the…

Transactional Communication Model

The most dynamic model of communication, in which all parties are simultaneously senders and receivers, co-creating meaning through instantaneous, continuous feedback. In this model, communication is a collaborative process where context, environment, and shared understanding…

Transcription(also: Speech-to-Text Transcription, Real-Time Transcription)

The process of converting spoken language into written text, either in real time or after the fact. In accessibility contexts, transcription services provide communication access for deaf and hard of hearing individuals by producing text versions of spoken content in classrooms,…

Translanguaging

The practice of drawing on multiple languages within a single interaction or communication act, leveraging a person's full linguistic repertoire rather than treating languages as separate, bounded systems. Translanguaging is particularly relevant to accessibility for…

Transliteration(also: Sign Language Transliteration)

The word-by-word conversion of text from one system into another — for example, rendering a name in one script using the characters of another. In sign-language accessibility the term has a specific meaning: producing a signed form of spoken or written English by substituting a…

Trouble-Indicating Behavior(also: TIB, Trouble Source-Repair)

Verbal or nonverbal behaviors that signal confusion, misunderstanding, or difficulty in communication. In research on dementia and human-robot interaction, TIBs are categorized into types including: requests for repetition, requests for clarification, metalinguistic comments ("I…

Turn Taking(also: Conversational Turn-Taking, Turn-Taking)

The pragmatic skill of alternating speaking and listening roles during conversation, including knowing when to speak, how long to speak, and how to signal readiness to yield or take a turn. Turn taking is a fundamental component of social communication that children typically…

Turn-Taking(also: Conversational Turn-Taking, Floor Management)

The process by which speakers in a conversation negotiate who speaks when, managing transitions between speakers through verbal and non-verbal cues. Turn-taking involves recognizing when a speaker is finishing, signaling desire to speak, and yielding the floor to others. In AAC…

Turn-Taking

The process by which participants in a conversation manage who speaks when, including how speakers signal they are finished and how listeners indicate they want to contribute. Turn-taking norms are typically based on spoken communication speeds and can create significant…

Unaided AAC(also: Unaided Augmentative and Alternative Communication, Body-Based AAC)

The branch of Augmentative and Alternative Communication that relies solely on the user's body — gestures, facial expressions, vocalisations, manual signs, body orientation — without an external device. Unaided AAC is fast, always available, and naturally expressive; families,…

VR-ASL(also: Virtual Reality American Sign Language)

A simplified adaptation of American Sign Language (ASL) designed for use in virtual reality environments where current controller tracking technology cannot capture the full range of hand and finger movements required for standard ASL. VR-ASL modifies or substitutes signs to…

Video Communication(also: Video Relay, Video-Based Communication)

The use of video technology for real-time or asynchronous communication, including video calls, video messages, and video posts on social media. Video communication is the primary medium for remote sign language use, as sign languages require visual transmission of hand…

Video Phone(also: Videophone, VP)

A telecommunications device that enables real-time video and audio communication between two or more parties. For Deaf and hard of hearing people, video phones are essential communication tools that allow conversation in sign language over distance, providing functional…

Video Remote Interpreter(also: VRI, Video Remote Interpreting, Video Relay Interpreting)

A video telecommunication service that provides sign language interpretation remotely via video connection. VRI allows deaf or hard of hearing individuals to communicate with hearing people through an off-site interpreter who appears on a screen, translating between sign…

Videoconferencing(also: Video Conferencing, Video Calling, Video Meetings)

Real-time audio-and-video communication between two or more people over a network, typically mediated by a software platform such as Zoom, Microsoft Teams, Google Meet, WhatsApp, or WeChat. Videoconferencing is a significant accessibility touchpoint: it can lower barriers for…

Viseme(also: Visual Phoneme)

The visual equivalent of a phoneme — the distinct mouth shape or lip position that corresponds to a speech sound as seen on a speaker's face. Unlike phonemes, which are auditory units, visemes are visual units that represent how the mouth looks during speech production. Multiple…

Visual Communication(also: VIC)

A method of conveying information, ideas, and meaning through visual elements such as images, icons, symbols, and pictographs rather than through spoken or written language. In accessibility contexts, visual communication systems are particularly important for people with…

Visual Interpretation Services(also: VIS, Remote Sighted Assistance, Visual Assistance Services)

Visual interpretation services are technology platforms that connect blind and low vision users with sighted assistants (either human volunteers or paid professionals) who provide real-time visual descriptions through video calls or image sharing. Services like Aira and Be My…

Visual Scene Display(also: VSD)

A type of augmentative and alternative communication (AAC) layout that uses photographs or images of real-world scenes with embedded interactive hotspots that produce speech output when selected. Unlike grid displays that present abstract symbols in rows and columns, VSDs ground…

Visual Supports(also: Visual Aids, Visual Cues)

Pictures, symbols, photographs, written words, objects, or other visual items used to support communication, learning, and behaviour in individuals with developmental disabilities, particularly autism. Visual supports leverage the strong visual processing abilities common among…

Visual Vocabulary(also: Picture-Based Vocabulary, Icon Vocabulary)

A collection of words or concepts represented through images, icons, or pictorial symbols rather than text alone. Visual vocabularies are widely used in augmentative and alternative communication (AAC) systems to support people who have difficulty with text-based language,…

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 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…

Voice over IP(also: VoIP, Internet Telephony, IP Telephony)

Technology that enables voice communication over internet protocol networks rather than traditional telephone lines. VoIP applications such as Skype, Zoom, and Teams allow voice and video calls over the internet at low cost. For accessibility, VoIP presents both opportunities…

Voice prosthesis(also: speech prosthesis, voice restoration device)

A device that enables speech production for people who have lost their natural voice, typically due to laryngectomy or severe laryngeal damage. Voice prostheses include external devices like electrolarynx (which produces vibrations held against the neck or inserted into the…

Voice rest(also: vocal rest, voice therapy)

A prescribed period of reduced or eliminated voice use, typically following laryngeal surgery, vocal cord injury, or to treat voice disorders. During voice rest, patients may be instructed to whisper or remain completely silent, relying on written communication, AAC devices, or…

Wideband Audio(also: HD Voice, High-Definition Audio)

Audio transmission that captures a broader range of frequencies (typically 50-7000 Hz or higher) compared to narrowband telephony (300-3400 Hz), resulting in clearer and more natural-sounding speech. In accessibility contexts, wideband audio is particularly important for hearing…

Word Board(also: Communication Board, Word Display)

A communication tool used in augmentative and alternative communication (AAC) consisting of words, common phrases, and sometimes alphabet letters arranged on a physical board or digital display. Users compose messages by pointing to items on the board. Words are typically…

Word-Finding Difficulty(also: Anomia, Word Retrieval Difficulty, Tip-of-the-Tongue)

A common symptom of aphasia where a person knows what they want to say but cannot retrieve the correct word. Word-finding difficulties can range from occasional pauses to severe impairment where even common words become inaccessible. The experience is often described as having a…

Written Choice(also: Written Choice Technique)

A therapeutic communication technique used with individuals who have aphasia, in which a conversation partner asks a question and then provides anticipated written answers for the person to choose from. This scaffolded approach reduces the language production demands on the…