Glossary

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Contextual Reinforcement(also: Header Reinforcement)

A technique in aural and non-visual rendering of tabular data where column headers, row labels, or other structural context is repeated alongside data values to help users understand the relationships between cells. Without contextual reinforcement, a screen reader might…

Continual Learning(also: Continuous Learning, Lifelong Learning, Never-ending Learning)

A machine learning paradigm in which models learn incrementally from new data over time while retaining previously acquired knowledge, rather than being trained once on a fixed dataset. Continual learning is relevant to accessibility because it enables AI-powered accessibility…

Continuing Bonds

Continuing bonds is a theory of grief, developed by Klass, Silverman and Nickman in the 1990s, which holds that healthy mourning often involves maintaining an ongoing relationship with a deceased or absent loved one rather than achieving closure and 'letting go'.…

Continuing Professional Development(also: CPD, Professional Development)

The ongoing process through which professionals maintain, update, and expand their knowledge and skills throughout their careers. In the context of digital accessibility, CPD programs train developers, designers, content creators, and educators on inclusive design practices,…

Continuous Input(also: Continuous Control, Analog Input)

Continuous input is any interaction technique in which the user varies a parameter smoothly along a range rather than selecting from a set of discrete options — adjusting a slider, dragging a brush, turning a dial, holding a gesture, or modulating vocal loudness. Continuous…

Continuous Integration/Continuous Delivery(also: CI/CD, Continuous Integration, Continuous Delivery)

Continuous Integration/Continuous Delivery (CI/CD) is a software development practice where code changes are automatically built, tested, and prepared for release on an ongoing basis. In accessibility practice, CI/CD pipelines can incorporate automated accessibility testing…

Continuous Motion Input(also: Gesture Typing, Swipe Input)

A text entry method where the user traces a continuous path across an on-screen keyboard, passing through the desired letters or keys without lifting their finger. This approach can be faster than discrete tapping and is particularly beneficial for users with motor impairments…

Continuous Sign Language(also: Connected Sign Language, Continuous Signing)

Sign language produced in natural, flowing sentences and discourse, as opposed to isolated individual signs. Continuous sign language includes phenomena like co-articulation (where one sign influences the formation of the next), epenthesis (insertion of transitional movements…

Continuous Sign Language Recognition(also: CSLR)

A computer vision task that involves recognizing sign language from continuous, naturally produced signing — as opposed to isolated sign recognition, which identifies individual signs in segmented clips. Continuous sign language recognition deals with the complexities of natural…

Continuous Specification(also: Continuous Positioning, Continuous Cursor Movement)

In cursor control interfaces, a positioning method where the cursor moves steadily in a given direction at a controlled rate until the user signals it to stop. This approach allows precise positioning because the user can halt movement at exactly the desired location, but it is…

Continuous Voice Control(also: Continuous Vocal Control, Proportional Voice Control)

A voice interaction paradigm in which vocal parameters such as pitch, loudness, vowel quality, and timbre are used to provide smooth, proportional, real-time control of a system, as opposed to discrete voice commands that trigger specific actions. Continuous voice control is…

Contrast Ratio(also: Color Contrast Ratio, Luminance Contrast Ratio)

A numerical measure of the difference in perceived brightness between two colors, expressed as a ratio ranging from 1:1 (no contrast) to 21:1 (maximum contrast, black on white). WCAG 2.2 requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text (Level…

Contrast Sensitivity

The ability to distinguish between objects and their background based on differences in luminance or color. Contrast sensitivity is distinct from visual acuity and can be reduced even when acuity is relatively preserved. People with poor contrast sensitivity may struggle to read…

Contrastive Decoding(also: Visual Contrastive Decoding, VCD)

Contrastive decoding is a technique for reducing hallucinations in large language model and multimodal AI outputs by comparing token probability distributions across different input conditions. The core principle is that tokens genuinely grounded in the input content will change…

Contrastive Learning(also: Contrastive Self-Supervised Learning)

Contrastive learning is a machine learning technique that trains models to produce vector embeddings by maximising similarity between representations of the same or augmented instance (positive pairs) while minimising similarity between representations of different instances…

Control Surface(also: Hardware Controller, Mixing Console Controller)

A control surface is a hardware device with physical knobs, sliders, and buttons that maps to the controls of a software application, most commonly a digital audio workstation (DAW). For people with visual impairments, control surfaces provide essential tactile access to…

Controlled Language(also: Controlled Natural Language, CL)

An explicitly defined restriction of a natural language that specifies constraints on vocabulary, grammar, and style to improve clarity, consistency, and machine processability of text. In accessibility, controlled language rules can be applied to improve the quality of content…

Controlled Language(also: CL, Controlled Natural Language)

A restricted subset of a natural language that limits vocabulary, grammar, and style to reduce ambiguity and improve clarity and consistency in writing. In accessibility, controlled language rules can be applied to verify and improve the quality of text alternatives for images,…

Convenience Sampling(also: Availability Sampling, Accidental Sampling)

A non-probability sampling method in which participants are selected based on their availability and willingness to participate rather than through systematic selection criteria. In accessibility research, convenience sampling often results in recruiting participants from the…

Convergence Insufficiency(also: CI)

A binocular vision disorder in which the eyes have difficulty turning inward (converging) to focus on nearby objects, causing symptoms such as double vision, eye strain, headaches, difficulty reading, and blurred vision during close work. Convergence insufficiency affects an…

Conversation Analysis(also: CA)

A qualitative research methodology that studies the sequential organization and interactional dynamics of naturally occurring talk and social interaction. Conversation analysis examines fine-grained details such as turn-taking, pauses, overlapping speech, gaze direction,…

Conversational AI(also: Chat AI, AI Chatbot)

Artificial intelligence systems designed to engage in dialogue with users through natural language, including chatbots, virtual assistants, and generative AI interfaces. Conversational AI has accessibility implications both as an interaction paradigm that can be more accessible…

Conversational Agency(also: Communicative Agency)

An individual's capacity to express themselves and achieve their communicative goals within a conversation. Conversational agency encompasses not just the ability to transmit messages but also the ability to shape conversation flow, express personality, negotiate meaning, and…

Conversational Agent(also: Chatbot, Virtual Assistant, AI Assistant)

A software system that uses natural language processing to engage in dialogue with users, answering questions and providing information through text or speech. In accessibility contexts, conversational agents offer potential for flexible, on-demand information access that can…

Conversational Assistant(also: Voice Assistant, Virtual Assistant, Intelligent Personal Assistant)

A software application that uses natural language processing and speech recognition to interact with users through spoken or typed conversation, providing information, performing tasks, and controlling devices. Examples include Google Assistant, Amazon Alexa, Apple Siri, and…

Conversational Flow(also: Dialogue Flow, Conversation Rhythm)

The natural rhythm and progression of a conversation, including the smooth exchange of turns, timely responses, appropriate pauses, and coherent topic development. Conversational flow depends on both partners' ability to produce and perceive turn-taking cues, backchanneling…

Conversational Gesture(also: Interaction Gesture, Dialogue Primitive)

A conversational gesture is an atomic building block of human-computer dialogue — a simple, well-defined interaction pattern that enables communication between user and machine. In graphical user interfaces, conversational gestures are realised through widgets such as list…

Conversational Glanceability(also: Conversational Layout Support)

A proposed design approach that uses conversational AI agents to provide blind and visually impaired users with the equivalent of visual glanceability—the ability to quickly scan and identify content of interest on a page. Sighted users can rapidly skim visual layouts to locate…

Conversational Interface(also: Conversational UI, Voice User Interface, VUI)

A user interface that enables interaction through natural language, either spoken or typed, allowing users to communicate with a system using conversational dialogue rather than traditional graphical controls. Conversational interfaces include voice assistants, chatbots, and…

Conversational Interface(also: Conversational UI, Conversational User Interface, Chat Interface)

An interface that enables interaction through natural language dialogue, either spoken or text-based, rather than through traditional graphical controls like buttons and menus. Conversational interfaces are significant for accessibility because they can reduce cognitive load,…

Conversational Management(also: Conversation Management, Interactional Management)

The processes by which interlocutors jointly regulate the structure of a conversation - taking and ceding turns, pre-empting interruptions, shifting attention and topic, repairing misunderstandings, and maintaining flow over time. In AAC research, conversational management is a…

Conversational Programming(also: natural language programming, LLM-driven scene modification)

Conversational programming is a paradigm in which users modify software behaviour or digital environments through natural language dialogue with an AI system, rather than through traditional developer-defined controls, menus, or code. In accessibility contexts, conversational…

Conversational Scaffolding(also: Scaffolded Interaction)

Human or technology-provided support, prompts, or guidance that helps individuals accomplish communication tasks they might struggle with independently. In voice assistant contexts, scaffolding includes features like setting up calendars, providing reminders, and offering…

Conversational Search(also: conversational information retrieval, chat-based search)

Conversational search is an approach to information retrieval in which users interact with a system through natural language dialogue rather than keyword queries, enabling multi-turn exchanges that iteratively refine information needs. For accessibility, conversational search…

Conversational User Interface(also: CUI, Conversational Interface, Dialogue Interface)

A user interface that enables interaction through natural language conversation, either via voice (spoken dialogue) or text (chat). Conversational user interfaces encompass voice assistants, chatbots, and dialogue systems that interpret user intent and respond in natural…

Convivial Tools(also: Conviviality)

A concept from philosopher Ivan Illich describing tools that are easy to learn through use, allow users to decide when and how to use them, and can adapt to individual preferences. In accessibility contexts, convivial tools are malleable technologies that empower users—including…

Convolutional Neural Network(also: CNN, ConvNet)

A class of deep neural network that uses convolutional filters to automatically extract spatial features from data, originally designed for image processing but now widely applied to sensor data, audio, and video analysis. CNNs identify patterns like edges, textures, and shapes…

Cookie Notice(also: Cookie Banner, Cookie Consent Banner, Cookie Popup)

A user interface element that appears on websites to inform visitors about the use of cookies and other tracking technologies, typically requesting consent to store data on their device. Cookie notices are required under privacy regulations like GDPR and the ePrivacy Directive.…

Cooperative Evaluation(also: Cooperative Usability Evaluation, Modified Think-Aloud)

A usability evaluation method in which the researcher and participant work together as collaborators rather than following a strict observer-subject protocol. Unlike standard controlled experiments, cooperative evaluation allows participants to think aloud, ask questions, and…

Cooperative Inquiry(also: Co-Inquiry)

A participatory design methodology that involves children as full design partners throughout the technology development process, from initial brainstorming through prototyping and evaluation. Developed by Allison Druin and colleagues, cooperative inquiry treats children not…

Coordinated Views(also: Linked Views, Coordinated Multiple Views, Brushing and Linking)

A data visualization technique in which multiple representations of the same dataset are displayed simultaneously and kept synchronized, so that actions in one view (such as selecting, filtering, or sorting) are immediately reflected in all other views. In accessible data…

Copilot (Shared Control)(also: Gaming Copilot, Assistive Copilot)

In shared-control video gaming, the copilot is the secondary actor who supports the pilot (the primary player, typically a person with a disability) by taking over game actions the pilot cannot perform. A copilot can be a human partner — often a family member, friend, or trained…

Coping Strategies(also: Coping Tactics, Workaround Strategies)

The techniques and approaches that users with disabilities develop to navigate around accessibility barriers they encounter on the web and in digital interfaces. Expert screen reader users, for example, employ strategies such as using element lists, virtual search, heading…

Coping Strategy(also: Coping Behavior, Adaptive Strategy)

A behavioral pattern or workaround that users with disabilities employ when encountering inaccessible digital content or interfaces. Coping strategies emerge when technology fails to meet accessibility needs, forcing users to develop alternative approaches such as skipping…

Core Haptics

Apple's iOS framework for designing and playing custom vibrotactile patterns on iPhone using the Taptic Engine. Core Haptics lets developers synthesize transient 'taps' and continuous vibrations, vary intensity and sharpness over time, and synchronize haptics with audio using…

Core Vocabulary(also: Core Words)

A small set of high-frequency words — typically pronouns, verbs, adjectives, and prepositions — that make up approximately 80% of what people say in everyday communication. Examples include words like "I," "want," "go," "more," "help," and "that." In AAC practice, core…

Coreference(also: Coreference Resolution, Anaphora Resolution)

The linguistic phenomenon of two or more expressions in a text referring to the same real-world entity — for example, "Sam", "she", and "the scientist" all referring to the same person. Coreference resolution is the NLP task of automatically linking these expressions into…

Corneal Reflection(also: Pupil-Center Corneal Reflection, PCCR)

An eye tracking technique that works by shining a near-infrared light at the eye and measuring the relationship between the reflection off the cornea (the bright spot called the glint) and the center of the pupil. As the eye rotates to look at different screen positions, the…

Corporate Accessibility(also: Enterprise Accessibility, Organizational Accessibility Programme)

The structured efforts by companies and organisations to ensure their products, services, and communications are accessible to people with disabilities. Corporate accessibility encompasses accessibility policies, dedicated accessibility teams, feedback channels for users with…

Corpus(also: Language Corpus, Text Corpus, British National Corpus)

A corpus is a large, structured collection of texts used to train, tune, or evaluate language-processing systems. Representative examples include the British National Corpus (BNC, 100 million words of British English), the Penn Treebank, and more recently Common Crawl and…