Glossary

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Newsela

An educational content platform that publishes news articles in multiple professionally-edited versions simplified to different U.S. school reading levels, enabling teachers to assign the same story at grade-appropriate difficulty. Because Newsela pairs original articles with…

Node Map(also: Topological node map, Graph map)

A graph-based representation of a walkable space in which each node corresponds to a meaningful point — typically an intersection, a destination (room, exit, stairwell), or the user's current position — and each edge corresponds to a traversable corridor or path. Node maps are…

Node-Link Diagram

A visual representation in which discrete entities (nodes) are drawn as shapes such as circles or boxes and relationships between them are drawn as connecting lines or arrows (links/edges). Node-link diagrams are the default visualization for trees, graphs, flowcharts,…

Noise Sensitivity(also: Auditory Hypersensitivity, Hyperacusis, Sound Sensitivity)

A heightened physiological and emotional response to sounds that others may tolerate without difficulty. Common among autistic individuals and people with other sensory processing differences, noise sensitivity can cause distress, anxiety, and sensory overload in everyday…

Noise sensitivity(also: Sound sensitivity, Auditory hypersensitivity)

A condition in which sounds that most people find tolerable are experienced as disproportionately distressing, overwhelming, or physically painful. Noise sensitivity exists on a spectrum from mild annoyance to extreme pain, and is common among neurodivergent individuals…

Nomadic Text Entry(also: Mobile Text Entry, On-the-Go Texting)

The practice of inputting text on a mobile device while moving through or actively engaging with the physical environment, as opposed to typing while stationary. For people who are blind or visually impaired, nomadic text entry presents unique challenges because it requires…

Non-Contact Haptics(also: Contactless Haptics, Device-Free Haptics)

A class of haptic feedback techniques that render tactile sensations on the user's body without requiring physical contact with a device, surface, or wearable. Common approaches include mid-air ultrasound haptics, air-vortex rings, and laser-induced plasma. Because they avoid…

Non-Functional Requirement(also: NFR, Quality Attribute)

A software requirement that specifies how a system should behave rather than what it should do. Non-functional requirements include accessibility, security, performance, maintainability, and usability. In web development, accessibility is a critical non-functional requirement…

Non-Manual Features(also: NMF, Non-Manual Markers, Non-Manual Signals)

The facial expressions, mouth movements, eye gaze, head tilts, and body postures that convey grammatical and semantic information in sign languages, functioning alongside manual hand signs. Non-manual features can indicate questions (raised eyebrows), negation (head shake),…

Non-Manual Markers(also: NMMs, Non-Manual Signals, Facial Grammar)

Grammatical elements in sign languages conveyed through facial expressions, head movements, eye gaze, and body posture rather than hand movements. In American Sign Language, non-manual markers are essential for conveying grammatical information such as questions (raised eyebrows…

Non-Manual Markers(also: Non-Manual Signals, NMMs, Facial Grammar)

Facial expressions, head movements, eye gaze, mouth movements, and body postures that convey grammatical information in sign languages. Unlike facial expressions in spoken languages which primarily convey emotion, non-manual markers in sign languages serve linguistic functions:…

Non-Manual Sign(also: NMS, Non-Manual Marker, Non-Manual Signal)

Facial expressions, head movements, eye gaze, mouth movements, and body posture that serve essential grammatical and linguistic functions in sign languages. In ASL, NMS perform lexical functions (distinguishing between signs like CLEAN and VERY CLEAN), morphological functions…

Non-Manual Signal(also: NMS, Non-Manual Marker, NMM)

A linguistic component of sign languages that is expressed through parts of the body other than the hands, including facial expressions, eyebrow movement, head tilts, shoulder shifts, mouth movements, and eye gaze direction. Non-manual signals serve critical grammatical…

Non-Manual Signals(also: Non-Manual Markers, NMS, NMM)

Linguistic information conveyed through parts of the body other than the hands in sign languages, including facial expressions, mouth movements, eye gaze, head tilts, head shakes, and body shifts. In American Sign Language and other sign languages, non-manual signals serve…

Non-Manual Signs(also: Non-Manual Markers, NMS, NMM)

Components of sign language that are produced without the hands, including facial expressions, mouth movements, eye gaze direction, head tilts, body posture, and shoulder shifts. Non-manual signs are not merely expressive additions but are grammatically essential in sign…

Non-Participation

In Wenger's Communities of Practice framework, the active (rather than merely absent) relationships people have with a community they do not fully join. Wenger identifies four forms: compromise (stepping back to respect another's space), cover (disengaging from issues one feels…

Non-Pharmacological Intervention(also: NPI, Non-Drug Intervention)

A non-pharmacological intervention (NPI) is any therapeutic approach delivered without medication, including art and music therapy, reminiscence work, cognitive stimulation, exercise programmes, animal-assisted therapy, environmental modifications, structured social activity,…

Non-Speech Audio(also: Non-Verbal Audio, Non-Speech Sound)

Auditory output that conveys information through sounds other than spoken words — for example tones, clicks, earcons, auditory icons, musical motifs, or vowel-like timbres. Non-speech audio is widely used in accessibility because it can be faster and less cognitively demanding…

Non-Speech Captions(also: Non-Speech Sound Captions, Non-Dialogue Captions)

Textual descriptions of non-speech audio elements in media content, including environmental sounds, music, and sound effects, displayed as part of closed or open captions. Non-speech captions are essential for Deaf and Hard of Hearing viewers to access auditory information…

Non-Speech Information(also: NSI, Non-Dialogue Audio Information)

Any audio content in media that is not spoken dialogue, including environmental sounds, music, sound effects, and ambient noise. Non-speech information plays a critical role in storytelling by conveying mood, indicating off-screen events, and providing contextual cues. For…

Non-Speech Input(also: Non-Speech Acoustic Input, Non-Verbal Voice Input)

A method of controlling computers or devices using sounds produced by the human vocal tract that are not recognised words — such as humming, whistling, hissing, clicking, or varying pitch and volume. Unlike speech recognition, which must wait for a complete utterance before…

Non-Speech Sounds(also: Non-Speech Audio, Sound Effects)

Auditory content in media that is not spoken dialogue, including music, environmental noises, sound effects, laughter, applause, and other ambient sounds. Non-speech sounds carry important narrative, emotional, and contextual information that contributes to a viewer's…

Non-Use(also: Technology Non-Use, Technology Refusal)

A research tradition in HCI that takes seriously the choice not to use a technology — treating refusal, abandonment, and selective engagement as meaningful, reasoned behaviour rather than as failure. Non-use scholarship (Wyatt, Baumer, Satchell & Dourish, Waycott and colleagues)…

Non-Verbal Communication(also: Nonverbal Communication, NVC, Body Language)

Communication through means other than spoken or written words, including facial expressions, eye contact, gestures, body posture, touch, tone of voice, and spatial behavior. Non-verbal communication conveys emotions, attitudes, and social signals that complement, modify, or…

Non-Verbal Vocal Interface(also: NVVI, Non-Verbal Vocal Interaction)

An interaction method that uses non-speech vocal sounds — such as humming, hummed melodies, rhythmic patterns, or vowel sounds — to control a computer or communication device. Unlike speech recognition, which requires the user to produce intelligible words, non-verbal vocal…

Non-Verbal Vocalization(also: Non-Speech Vocalization, Vocal Gesture, Non-speech Vocalisation)

A sound produced by the voice that is not a spoken word, such as a sustained vowel sound ("Ahhhhh"), hum, or other vocal noise. In assistive technology and alternative input contexts, non-verbal vocalizations can serve as continuous control signals for cursor movement or other…

Non-Visual Cooking(also: Blind Cooking, Cooking Without Vision)

The practice of preparing food without relying on visual information, as performed by blind and low vision individuals. Non-visual cooking involves distinctive strategies including tactile exploration to locate and verify ingredients and tools, spatial memorization of kitchen…

Non-Visual Drawing(also: Blind Drawing, Drawing Without Sight)

The practice of creating graphical representations — such as diagrams, shapes, charts, or illustrations — without relying on visual feedback. Non-visual drawing can be accomplished through tactile methods (using raised line drawing kits or embossing tools), audio-tactile methods…

Non-Visual Exploration(also: Non-Visual Interaction, Non-Visual Scanning)

The process by which blind or visually impaired people gather information about their physical environment, documents, or interfaces without relying on sight. Non-visual exploration combines multiple strategies including touch, audio feedback, spatial memory, contextual…

Non-Visual Feedback(also: Non-Visual Output, Alternative Sensory Feedback)

Any system output or response that does not rely on vision to be perceived, including auditory cues (speech, tones, sonification), haptic feedback (vibrations, force), and tactile output (braille, raised surfaces). Non-visual feedback is essential for making interactive systems…

Non-Visual Interaction(also: Non-Visual Interface, Eyes-Free Interaction)

Interaction techniques and interface designs that do not require sight, enabling blind and low vision users to operate software and devices through alternative modalities such as speech, keyboard commands, haptic feedback, spatial audio, and gesture. In creative tools,…

Non-Visual Interaction(also: Non-Visual Access, Non-Visual Interface)

Methods of interacting with computer systems and digital content without relying on visual display. Non-visual interaction encompasses screen reader output, speech interfaces, keyboard navigation with audio feedback, braille displays, and haptic feedback. The Raman Principle…

Non-Visual Makeup(also: Blind Makeup Application, Accessible Makeup)

The practice and process of applying cosmetics without relying on visual feedback, as performed by people who are blind or have low vision. Non-visual makeup involves embodied, tactile-first strategies including finger-based product application for direct sensory feedback,…

Non-Visual Mental Model(also: Non-Visual Representation, Tactile Mental Model)

A cognitive representation of concepts, objects, or systems built through non-visual sensory channels — primarily touch, hearing, and proprioception — rather than through sight. People who are blind develop non-visual mental models that may differ structurally from visual models…

Non-Visual Navigation(also: Eyes-Free Navigation, Non-Visual Wayfinding)

Strategies and technologies that enable people who are blind or have low vision to navigate physical environments without relying on visual information. Non-visual navigation uses a combination of tactile cues (textured ground surfaces, cane feedback), auditory cues (traffic…

Non-Visual Reading(also: Audio Reading, Tactile Reading)

Methods of accessing written content without relying on visual perception, including braille reading, screen reader audio output, and text-to-speech technology. Non-visual reading is essential for blind users but presents unique challenges for navigation, skimming, and…

Non-Visual Reference Database(also: Non-Visual Cooking Database)

A proposed structured collection that maps common visual descriptions used in cooking and other domains to their non-visual equivalents using texture, sound, smell, time, and temperature descriptors. For example, mapping the visual instruction "cook until golden brown" to…

Non-Visual Skimming(also: Aural Skimming, Accessible Skimming)

Non-visual skimming is the process of quickly surveying and extracting key information from text content without visual access, typically through auditory means such as screen readers. While sighted users skim by rapidly scanning text with their eyes, blind users lack an…

Non-Visual Web Access(also: Non-Visual Browsing, Nonvisual Web Access)

The use of the web without relying on visual display, typically through screen readers, voice browsers, or refreshable braille displays that convert web content into speech or tactile output. Non-visual web access depends heavily on proper semantic HTML, alternative text for…

Non-Visual Web Browser(also: Self-Voicing Browser, Audio Web Browser, Talking Browser)

A web browser specifically designed for users who cannot see the screen, providing audio-based or haptic interfaces for navigating and interacting with web content. Unlike standard screen readers that overlay existing visual browsers, non-visual browsers are purpose-built to…

Non-diegetic Sound(also: Non-diegetic Audio, Extradiegetic Sound)

Sound in film, television, or games that does not originate from any source within the story world and cannot be heard by the characters - for example, orchestral score, voice-over narration, or added accessibility cues. This contrasts with diegetic sound, which exists in the…

Non-manual markers(also: NMM, Non-manual signals, Facial grammar)

Linguistic features in sign languages that are conveyed through facial expressions, head tilts, eye gaze direction, mouth movements, and body posture rather than through hand signs. Non-manual markers serve grammatical functions in ASL and other sign languages — including…

Non-visible disability(also: Hidden disability, Non-apparent disability)

A disability that is not immediately apparent to others through visual observation. Non-visible disabilities include neurodivergent conditions (autism, ADHD, dyslexia), mental health conditions (anxiety, depression, PTSD), chronic pain, chronic fatigue, diabetes, epilepsy, and…

Non-visual Display(also: Nonvisual Display, Non-visual Interface)

A non-visual display presents information to a user through senses other than vision — most commonly hearing (synthesized speech, earcons, sonification), touch (Braille output, vibrotactile patterns, force-feedback haptics), or combinations thereof. Non-visual displays are…

Nonspeech Audio(also: Non-Speech Sounds, Auditory Cues)

Audio feedback in user interfaces that conveys information through sounds other than synthesized or recorded speech, including earcons (abstract musical motifs), auditory icons (realistic sounds representing actions or objects), and sonification (data mapped to sound…

Nontraditional Assistive Technologies(also: NTATs, Nontraditional Input Technologies)

Input technologies that use physiological signals rather than physical movement to control computers, providing access for people who cannot use traditional devices like keyboards, mice, or even eye-tracking systems. NTATs include brain-computer interfaces (using EEG or fNIR),…

Nonverbal Learning Disorder(also: NVLD, Nonverbal Learning Disability, NLD)

A neurodevelopmental condition characterized by difficulties with visual-spatial processing, motor coordination, and social skills, while verbal abilities are typically a relative strength. People with NVLD may struggle with interpreting visual information, understanding spatial…

Nonverbal communication(also: NVC, Body language, Nonverbal cues)

The transmission of information through channels other than spoken or written language, including facial expressions, eye contact, head gestures, hand movements, body posture, spatial proximity, and tone of voice. Nonverbal communication conveys essential social information…

Nonvisual Access(also: Non-Visual Access, Nonvisual Web Access, Non-Visual Web Access)

The use of digital content, particularly web pages and applications, through means other than sight. Nonvisual access typically involves screen readers that convert text to speech, braille displays that render content tactilely, or other assistive technologies that present…

Nonvisual Accessibility(also: Non-Visual Access)

Nonvisual accessibility refers to approaches, strategies, and technologies that enable people who are blind or have low vision to access information and interact with digital and physical environments without relying on sight. This encompasses screen readers, braille displays,…