Glossary

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Swedish Sign Language(also: SSL, Svenskt teckenspråk)

The sign language used by the Deaf community in Sweden, recognized as an official minority language since 1981. Like other national sign languages, SSL is a complete natural language with its own grammar distinct from spoken Swedish. It uses manual signs (hand shapes, movements,…

Swell Form(also: Capsule Paper, Microcapsule Paper, Swell Touch Paper)

A tactile graphics production method using special heat-sensitive paper coated with microcapsules. When black ink is printed on the paper and passed through a heating machine, the dark areas absorb heat and swell, creating raised tactile surfaces. Swell Form is commonly used in…

Swell Paper(also: Capsule Paper, Microcapsule Paper, PIAF Paper)

A special paper coated with heat-sensitive microcapsules that swell when exposed to heat, creating raised tactile surfaces from printed black areas. When passed through a heating device (such as a PIAF — Pictures In A Flash — machine), dark-printed lines and shapes become raised…

Swift Playgrounds(also: Apple Swift Playgrounds)

A hybrid block-based and text-based programming environment developed by Apple for iPad and Mac that teaches coding using the Swift programming language. Swift Playgrounds is notable in the accessibility education space because it integrates with VoiceOver, includes tactile maps…

Switch(also: Adaptive Switch, Accessibility Switch)

An assistive technology input device that is activated by a single action such as pressing, squeezing, blowing, blinking, or moving a body part. Switches are designed for people with significant motor impairments who cannot use standard keyboards, mice, or touchscreens. They…

Switch Access(also: Switch Control, Switch Scanning)

A method of computer and device interaction that uses one or more switches as input devices, designed for people who cannot use standard keyboards, mice, or touchscreens due to motor impairments. Switch access is built into major operating systems (iOS Switch Control, Android…

Switch Keyboard(also: Scanning Keyboard, On-Screen Scanning Keyboard)

A switch keyboard is a virtual keyboard interface designed for people with severe motor disabilities who cannot use a standard keyboard or pointing device. It works through a scanning mechanism: a cursor automatically moves across rows and columns of the keyboard, and the user…

Switch Scanning(also: Scanning Mode, Auto Scanning)

An input method for assistive technology where options are sequentially highlighted (scanned) and the user activates a single switch to select the currently highlighted item. This enables people with severe motor disabilities to access computers, communication devices, and other…

Switch Scanning(also: Switch Access, Scanning Input)

An alternative input method in which items on a screen are sequentially highlighted and the user activates a switch to select the desired item when it is highlighted. Switch scanning is used by people with significant motor impairments who cannot use direct touch, a mouse, or a…

Sycophancy(also: AI Sycophancy, Sycophantic AI)

A behavioral tendency in large language models to agree with, flatter, or validate the user's stated views and self-assessments rather than offer accurate or critical feedback - even when the user is mistaken or self-defeating. Sycophancy emerges from training methods that…

Symbiotic Learning

Symbiotic Learning is a conceptual framing introduced by Jiang et al. (CHI 2026) describing a mode of mixed-ability family learning in which parents and children mutually enable each other's participation and development through AI-mediated communication. Rather than positioning…

Symbol Communication(also: Symbol-Supported Communication)

The use of graphic symbols — pictograms, ideograms, line drawings, or photographs — alongside or in place of text to convey meaning. Symbol communication supports people who cannot rely on spoken or written language, including many AAC users, children and adults with…

Symbol Selection Set(also: Symbol Board, Communication Board)

A structured collection of graphic symbols, words, or phrases arranged in a grid or other layout for use in augmentative and alternative communication (AAC). Users select symbols to compose messages, with each symbol representing a word, phrase, concept, or action. Selection…

Symbol-Based Communication(also: Picture-Based Communication, Graphic Symbol Communication)

A form of augmentative communication that uses visual symbols — including pictures, photographs, line drawings, or icons — to represent words, concepts, or messages. Symbol-based communication is particularly useful for people with limited literacy, intellectual disabilities, or…

Symbol-based AAC(also: Picture-based AAC, Pictographic AAC, Picture Communication Symbols)

Symbol-based AAC refers to augmentative and alternative communication systems whose vocabulary is represented by graphic symbols, line drawings, photographs, or pictograms rather than (or alongside) written words. Users select symbols on a paper board, a dedicated…

Symbolic Communication(also: Symbol-Based Communication)

Communication that uses symbols — including spoken words, written text, manual signs, pictures, or graphic icons — to represent meanings, objects, actions, or concepts. Developing symbolic communication is a critical milestone for emergent communicators, as it enables more…

Symbolic Interactionism(also: SI)

A sociological tradition, associated with Herbert Blumer and the Chicago School following George Herbert Mead, that understands social reality as constructed through ongoing interaction: people act toward things — including other people, technologies, and disability itself — on…

Symbrachydactyly

A rare congenital condition in which a child is born with abnormally short fingers that may be webbed, misshapen, or missing. The name combines "sym" (joined), "brachy" (short), and "dactyly" (finger). Typically only one hand is affected, and the underlying bone, muscle,…

Symptom Fluctuation(also: Fluctuating Symptoms, Variable Symptoms, Good Days and Bad Days)

The variation in symptom severity that people with chronic conditions or disabilities experience over time—sometimes within a single day. Symptom fluctuation means that a person's abilities and access needs may change unpredictably, making it difficult to follow fixed schedules…

Symptom Tracking(also: Symptom Monitoring, Symptom Logging)

The systematic recording of mental health symptoms, behaviors, triggers, and associated contexts over time to build self-awareness, identify patterns, and measure treatment progress. For OCD, symptom tracking may include logging triggers, compulsive behaviors, anxiety levels…

Synaesthesia(also: Synesthesia)

Synaesthesia is a perceptual phenomenon in which a stimulus in one sensory modality automatically and involuntarily triggers an additional experience in a different modality or sub-modality - for example, seeing specific colours when hearing musical notes (chromesthesia),…

Synchronous Communication(also: Real-Time Communication, Live Communication)

Communication that occurs in real time, requiring all participants to be present simultaneously. In digital contexts, this includes video conferencing, live chat, instant messaging, and real-time collaboration tools. While synchronous communication fosters immediacy and social…

Syntactic Accessibility(also: Technical Accessibility)

The dimension of web accessibility concerned with the correctness of code sent to the browser and assistive technologies. Syntactic accessibility focuses on whether HTML markup, ARIA attributes, and other technical elements conform to standards so that content can be properly…

Syntactic NMS(also: Syntactic Non-Manual Sign)

Non-manual signs that define sentence types and grammatical structure in sign languages. In ASL, syntactic NMS include raised eyebrows for Yes/No questions, furrowed brows and forward head tilt for WH-questions, head shake for negation, and specific facial configurations for…

Syntactic Parse Tree(also: Parse Tree, Syntactic Tree)

A tree-shaped data structure that represents the grammatical structure of a sentence according to a formal grammar. Internal nodes correspond to phrases (noun phrase, verb phrase, clause, sentence) and leaves correspond to individual words or signs. Parse trees are produced…

Syntactic Simplification(also: Sentence Simplification)

A form of text simplification that restructures complex sentences into simpler grammatical forms, such as splitting compound sentences, converting passive voice to active voice, or resolving relative clauses. Syntactic simplification reduces the cognitive load of parsing…

Syntactic Structure(also: Program Structure, Code Structure)

The hierarchical arrangement of elements in a programming language according to the language's grammar rules, including how statements, expressions, and blocks are nested and related to one another. In accessibility contexts, syntactic structure is significant because sighted…

Syntax Highlighting(also: Code Highlighting, Syntax Coloring)

A feature of text editors and IDEs that displays source code in different colors and fonts based on the category of terms—keywords, variables, strings, comments, and operators are visually distinguished to improve readability and help programmers identify syntax errors. While…

Syntax-Directed Editor(also: Structure Editor, Syntax-Aware Editor)

A code editor that understands the formal grammar of a programming language and uses this knowledge to guide editing operations. Unlike plain text editors, syntax-directed editors treat source code as a structured tree of language constructs rather than a sequence of characters.…

Synthesized Speech(also: Synthetic Speech, Speech Synthesis, TTS Output)

Computer-generated speech produced by text-to-speech (TTS) engines that convert written text into spoken audio output. Synthesized speech is the primary means by which screen readers convey on-screen content to blind and visually impaired users. While modern TTS voices have…

Synthesized Video Description(also: TTS Video Description, Text-to-Speech Description, Synthesized Audio Description)

An audio description for video content that is generated using text-to-speech (TTS) technology rather than recorded by a human narrator. A describer writes a text script describing the visual elements of a video, and speech synthesis software converts this text into spoken…

Synthetic Phonics(also: Phonics, Systematic Phonics)

A method of teaching reading that emphasises learning the sounds (phonemes) associated with letters and letter combinations, then blending those sounds together to form words. Unlike analytic phonics, which starts with whole words and breaks them down, synthetic phonics builds…

Synthetic Speech(also: Artificial Speech, Computer-generated Speech)

Speech that is artificially produced by computer systems rather than recorded from human speakers. Synthetic speech is the output of text-to-speech systems and is fundamental to screen readers and voice assistants. Modern synthetic speech uses various generation methods…

Synthetic Voice(also: Artificial Voice, Computer-Generated Voice, TTS Voice)

A digitally generated voice produced by text-to-speech technology, used by individuals with speech impairments as an alternative means of verbal communication. People who rely on synthetic voices for presentations, phone calls, or daily conversation must often invest…

System Access(also: SA, System Access to Go, SA To Go)

A screen reader for Windows developed by Serotek Corporation that was notable for offering a free version and a portable "To Go" edition that could run from a USB drive without installation. System Access was designed to provide an affordable alternative to commercial screen…

System Usability Scale(also: SUS)

A widely used 10-item Likert scale questionnaire developed by John Brooke in 1996 that provides a quick, reliable measure of perceived usability. Scores range from 0 to 100, with higher scores indicating better usability. The SUS has been validated across thousands of studies,…

System Usability Scale(also: SUS)

A widely used, standardized questionnaire consisting of 10 items that measures perceived usability of a system. Developed by John Brooke in 1986, SUS provides a "quick and dirty" reliable measure of usability. Each item uses a 5-point Likert scale, and the final score ranges…

System-Class Accessibility(also: Platform-Level Accessibility)

The architectural support built into an operating system to make the entire platform usable by people with disabilities. System-class accessibility encompasses three components: alternative input and output modalities (such as speech synthesis, braille displays, and switch…

Systematic Literature Review(also: SLR, Structured Literature Review)

A rigorous research methodology that systematically identifies, evaluates, and synthesizes all relevant studies on a particular topic using predefined criteria and transparent processes. Systematic literature reviews in accessibility research help map the state of the field,…

Systematic Review(also: Systematic Literature Review)

A systematic review is a rigorous, reproducible synthesis of research on a narrowly-defined question, using a pre-registered protocol, exhaustive database search, explicit inclusion and exclusion criteria, independent dual screening, formal quality appraisal, and - where…

Systems of Access

A conceptual framework describing the dynamic network of people, institutions, environments, and resources that disabled people navigate to meet their needs. Unlike linear models of accessibility that focus on removing individual barriers, systems of access recognizes that…