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Speaker Adaptation(also: Voice Adaptation, Speaker-Adaptive Training, Voice Personalization)

Speaker adaptation is the process of adjusting an existing automatic speech recognition (ASR) system — usually one trained on a large, demographically broad corpus of able-bodied speakers — to a particular individual's voice using a relatively small amount of that person's…

Speaker-dependent speech recognition(also: User-adapted ASR, Personalized speech recognition)

A speech recognition approach that trains or adapts its acoustic models to a specific individual's voice characteristics, rather than relying solely on general population models. For people with cognitive disabilities, dysarthria, or other speech differences, speaker-dependent…

Spearcon

A spearcon is a type of auditory icon created by compressing a spoken phrase until it becomes a very brief, distinctive audio cue. Unlike earcons, which use abstract musical sounds, spearcons retain a connection to the original speech, making them easier to learn and associate…

Speech Composer(also: Speech Generation, Message Composition Engine)

A software component in AAC (Augmentative and Alternative Communication) systems that takes user input — whether typed text, selected symbols, or telegraphic phrases — and processes it for spoken output through a text-to-speech synthesiser. Advanced speech composers may include…

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

An electronic device used in augmentative and alternative communication that produces speech output, either through pre-recorded messages or text-to-speech synthesis. Speech generating devices range from dedicated hardware devices (like the Accent1400) to software applications…

Speech Input(also: Voice input, Voice control, Speech recognition input)

An input method that allows users to control devices or enter text by speaking rather than using manual touch or keyboard input. Speech input is particularly important for people with visual impairments, who use it significantly more often than sighted users to overcome the…

Speech Neuroprosthesis(also: Speech BCI, Speech Brain-Computer Interface)

A brain-computer interface that decodes neural activity associated with attempted or imagined speech and converts it into text, synthesized voice, or both. Speech neuroprostheses are designed for people with anarthria or severe dysarthria from ALS, brainstem stroke, locked-in…

Speech Output(also: Auditory Feedback, Spoken Feedback)

Speech output refers to the use of synthesised or pre-recorded human voice to convey information from a computer system or device to a user. In accessibility contexts, speech output is a primary means of making visual interfaces accessible to blind and visually impaired users,…

Speech Recognition(also: Voice Recognition, STT, Speech-to-Text)

Technology that converts spoken language into text or commands by analyzing audio input. Speech recognition powers dictation systems, voice assistants, and voice-controlled interfaces. For accessibility, speech recognition enables text input and device control for users who…

Speech Rule Engine(also: SRE)

An open-source JavaScript library that generates speech and Braille output for mathematical expressions given in presentation MathML. The Speech Rule Engine performs semantic interpretation of mathematical formulas — analyzing symbols, determining operator scope, and building…

Speech Synthesis(also: Synthetic Speech, TTS Engine)

The artificial production of human speech by computer, most commonly used in text-to-speech (TTS) systems that convert written text into spoken audio. Speech synthesis is foundational to screen readers and other assistive technologies used by people with visual impairments and…

Speech Synthesizer(also: Speech Synthesiser, Text-to-Speech Engine, TTS Engine)

Software or hardware that converts text into spoken audio output, producing artificial speech that can be used to read content aloud. Speech synthesizers are a fundamental component of many assistive technologies, including screen readers for blind users and augmentative and…

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

A user interface that enables interaction with a computer or device primarily through spoken language rather than through physical input devices like keyboards, mice, or touchscreens. Speech user interfaces use speech recognition to interpret user commands and may provide…

Speech Visualization(also: Visual Speech Display, Speech-to-Visual Display)

Speech visualization refers to techniques that convert spoken language into visual representations to aid comprehension, particularly for individuals who are deaf or hard of hearing. These displays can range from real-time captioning and waveform displays to more abstract…

Speech-Based Cursor Control(also: Voice Cursor Control, Speech-Driven Pointing)

A method of controlling a computer's pointing cursor using spoken voice commands rather than a mouse, trackpad, or other physical pointing device. Users speak directional commands (such as "move left," "move up") to start cursor movement and a stop command to halt it, then issue…

Speech-Based Cursor Movement(also: Voice-Controlled Cursor, Voice Cursor Control)

A technique for moving the on-screen cursor using voice commands rather than physical manipulation of a pointing device. Speech-based cursor movement systems typically use one of two approaches: discrete specification, where the user speaks a command to jump the cursor to a…

Speech-Based Navigation(also: Audio Navigation, Speech-Based Web Navigation)

A method of navigating digital content, particularly web pages, using synthesised speech output rather than visual display. In speech-based navigation, users listen to content read aloud sequentially and use keyboard commands to move between elements. This approach is inherently…

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

An electronic AAC device that produces spoken output from text or symbol input, enabling people with speech disabilities to communicate verbally with others. Speech-generating devices range from dedicated hardware (such as Tobii Dynavox devices) to software applications running…

Speech-Language Pathologist(also: SLP, Speech Therapist, Speech-Language Therapist)

A healthcare professional who assesses, diagnoses, and treats communication and swallowing disorders across the lifespan. In the context of accessibility, SLPs play a central role in AAC intervention — evaluating individuals for AAC needs, selecting appropriate devices and…

Speech-to-Sign Translation(also: Spoken Language to Sign Language Translation)

The process of automatically converting spoken language into sign language output, typically displayed through a signing avatar or animated character. Speech-to-sign translation involves three major components: automatic speech recognition to convert audio to text or semantic…

Speech-to-Text(also: STT, Speech Recognition, Automatic Speech Recognition)

Technology that converts spoken language into written text, enabling voice-based input for digital systems. In accessibility, speech-to-text serves multiple roles: it powers voice command interfaces for users who cannot use keyboard or touch input, generates real-time captions…

Speed Dial(also: One-touch Dialing, Quick Dial)

Speed dial is a mobile or landline phone feature that lets a user place a call to a preset contact by pressing one or two assigned digits rather than entering a full phone number. Originally introduced as a convenience feature, speed dial functions as a meaningful accessibility…

Spell Checker(also: Spellchecker, Spelling Checker)

Software that identifies and suggests corrections for misspelled words in text. Standard spell checkers often fail to catch errors made by people with dyslexia because dyslexic spelling errors differ from typical misspellings — they may include real-word substitutions (e.g.,…

Split-Tap Gesture(also: Split Tap)

A two-finger touchscreen gesture where one finger holds position on an object while a second finger taps elsewhere on the screen to activate or select it. Originally developed for the Slide Rule screen reader, the split-tap gesture was adopted by mobile screen readers like…

Spoken Dialog System(also: SDS, Voice Dialog System, Conversational AI)

A computer system that uses speech as both input and output to conduct goal-oriented conversations with users. Unlike simple voice command systems, spoken dialog systems can handle multi-turn exchanges, track conversation context, manage misunderstandings, and adapt to user…

Spoken Dialogue System(also: SDS, Voice Dialogue System)

A computer system that communicates with users through spoken natural language, allowing them to interact via voice rather than visual or manual interfaces. Spoken dialogue systems are used in telecare, customer service, and home care applications, and are particularly relevant…

Stance-Control Orthosis(also: Stance-control KAFO, SCO, Stance-control knee-ankle-foot orthosis)

A class of knee-ankle-foot orthoses that lock the knee during the stance (weight-bearing) phase of gait to prevent buckling, but unlock it during the swing phase to allow natural knee flexion. Stance-control devices detect gait phase through joint-angle sensors,…

Steering Law(also: Accot-Zhai Steering Law)

A predictive model of human movement describing the time required to navigate a cursor through a constrained path, such as a tunnel or curved corridor on screen. Proposed by Accot and Zhai as an extension of Fitts's Law, the Steering Law accounts for tasks where the user must…

Stenographic Keyboard(also: Steno Machine, Stenotype, Shorthand Keyboard)

A specialized keyboard used by CART captioners and court reporters that allows simultaneous pressing of multiple keys to represent syllables, words, or phrases in a single stroke, enabling transcription speeds of 200+ words per minute. Each captioner maintains a personal…

Stenotype(also: Stenography, Shorthand Typing, Machine Shorthand)

A specialised text-entry method that uses a keyboard with fewer keys than a standard QWERTY layout, where multiple keys are pressed simultaneously (chording) to represent phonetic sounds, syllables, or entire words. Stenotype enables trained operators to achieve speeds of…

Step-by-Step Device(also: Sequential Message Device, Step-by-Step Communicator, SBS)

A simple, single-switch augmentative and alternative communication (AAC) device that stores a sequence of pre-recorded voice messages and plays them back one at a time with each button press. Step-by-step devices are categorised as "low-tech" or "mid-tech" AAC because they…

Stepwise pointing(also: Recursive target acquisition, Tile-based pointing)

A mouse emulation technique in which the screen is divided into a grid of tiles, the user selects a tile to zoom into it, the tile subdivides into smaller subtiles, and this process repeats until the desired screen location is reached at pixel-level precision. Stepwise pointing…

Stereo Panning(also: Audio Panning, Pan)

The technique of distributing a mono sound signal between the left and right channels of a stereo output to create the perception that the sound originates from a specific horizontal position in space. A fully left-panned sound plays only in the left ear, a centered sound plays…

Stereo Vision(also: Stereoscopic Vision, Stereo Camera System, Stereopsis)

A computer vision technique that uses two or more cameras positioned at slightly different viewpoints to extract three-dimensional depth information from a scene, mimicking the way human binocular vision perceives depth. In assistive technology, stereo vision systems have been…

Stereoscopic Camera(also: Stereo Camera, Depth Camera, 3D Camera)

A camera system that uses two or more lenses to capture images from slightly different perspectives, mimicking human binocular vision to compute depth information (disparity maps). In accessibility applications, stereoscopic cameras are used in assistive devices for visually…

Sticky Keys(also: Sequential Key Entry)

An operating system accessibility feature that allows users to press modifier keys (Shift, Ctrl, Alt, Command) sequentially rather than simultaneously, making keyboard shortcuts accessible to people who can only press one key at a time. Sticky Keys is built into Windows, macOS,…

Structural Abstraction(also: Formula Abstraction, Expression Collapsing)

Structural abstraction is an accessibility technique that simplifies complex visual structures — particularly mathematical formulas — by initially collapsing sub-expressions into symbolic summaries and allowing users to progressively expand and explore them at their own pace.…

Structured Audio(also: Structured Digital Audio)

Structured audio refers to digital audio content that has been encoded with hierarchical markers and metadata, allowing non-sequential access to specific segments such as chapters, sections, paragraphs, and phrases. Unlike linear audio recordings (such as traditional audio…

Stylus(also: Digital Pen, Active Pen)

A pen-shaped input device used to interact with touchscreens, tablets, and other digitizer surfaces. Unlike finger touch, styluses provide a smaller contact point for precise selection, and active styluses can detect pressure, tilt, and hover states. For accessibility, styluses…

Subvocal Input(also: Subvocal Control, Subvocalisation Input)

An input method that uses very quiet or nearly silent vocalisations — sounds produced with minimal vocal effort that are typically inaudible to nearby people. Subvocal input includes techniques such as humming, whispering, or producing sounds detectable only by bone-conduction…

Suitcase Robot(also: Suitcase-shaped robot, Robotic suitcase)

A class of autonomous navigation robots housed inside a rolling suitcase or carry-on-shaped enclosure, designed so that a blind or low-vision user can grip the handle and be guided to a destination while appearing to any onlooker to simply be walking with a piece of luggage. The…

Surface Electromyography(also: sEMG, Surface EMG)

A non-invasive technique for measuring the electrical activity produced by skeletal muscles, using electrodes placed on the skin over the muscle. Surface EMG is used in biomechanics, prosthetic control, rehabilitation, and — increasingly — as an input modality for accessible…

Surface Haptics(also: Surface Haptic Technology)

A branch of haptic technology that creates tactile sensations directly on a flat surface, such as a touchscreen, by modulating the friction between a fingertip and the display. Unlike conventional vibration motors that shake the entire device, surface haptics produces localised…

Surround sound(also: Multichannel audio, 5.1 audio, 7.1 audio)

An audio reproduction technique that uses multiple speaker channels arranged around the listener to create an enveloping sound field. Common configurations include 5.1 (five speakers plus a subwoofer) and 7.1 (seven speakers plus a subwoofer), where speakers are placed at…

Swarm robotics(also: Multi-robot systems)

A field of robotics involving the coordination of multiple simple robots that work together as a group, inspired by collective behaviours in nature such as ant colonies or bird flocking. Individual robots follow simple rules, but their collective behaviour produces complex,…

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…

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…