Glossary

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N-gram(also: Bigram, Trigram, Unigram)

A contiguous sequence of n items (typically words) from a text, used in language modeling to predict the probability of a word based on its predecessors. A unigram considers single words in isolation, a bigram considers pairs of consecutive words, and a trigram considers…

NFC(also: Near Field Communication)

A short-range wireless communication technology that enables data exchange between devices held within a few centimetres of each other. NFC is built into most modern smartphones and can read passive NFC tags embedded in objects. In accessibility applications, NFC tags can be…

NFC Tag(also: Near Field Communication Tag, NFC)

An NFC (Near Field Communication) tag is a small, unpowered chip that can transmit data to a compatible smartphone or device when held within a few centimeters. In accessibility contexts, NFC tags are used in museums, galleries, and public spaces to provide on-demand information…

NFC accessibility(also: NFC tags for accessibility)

The use of Near Field Communication (NFC) technology to make physical objects, materials, and environments accessible to people with disabilities. NFC tags can be embedded in physical cards, objects, or locations and triggered by tapping a smartphone or dedicated reader to…

NVDA(also: NonVisual Desktop Access)

A free, open-source screen reader for Windows developed by NV Access. NVDA provides speech and braille output, enabling blind and low-vision users to interact with the operating system, web browsers, and applications. Since its release in 2006, NVDA has become one of the most…

NVDA(also: NonVisual Desktop Access)

A free, open-source screen reader for Microsoft Windows developed by NV Access. NVDA enables people who are blind or have low vision to use computers by reading on-screen text aloud through a speech synthesizer or outputting to a refreshable Braille display. As open-source…

Narrative Route Description(also: Verbal Route Guidance, Turn-by-Turn Narrative)

A structured verbal representation of a travel route that guides users through sequential steps using spoken or text-based instructions. Effective narrative descriptions for blind travelers typically follow a consistent format: action to take, distance information, then landmark…

Narrator(also: Windows Narrator)

The built-in screen reader included with Microsoft Windows operating systems. Narrator reads aloud text on screen, describes notifications and interface elements, and allows users to navigate Windows and applications using keyboard commands. First introduced in Windows 2000 as a…

Natural Language Generation(also: NLG, Text Generation)

A subfield of artificial intelligence and computational linguistics focused on automatically producing human-readable text from structured data or other non-linguistic representations. In accessibility, natural language generation is used to create textual descriptions of visual…

Natural Language Interface(also: NLI, Natural Language User Interface)

A user interface that allows people to interact with technology using everyday language rather than specialized commands, menus, or graphical controls. Natural language interfaces can improve accessibility by reducing the learning curve for technology use, supporting users with…

Natural Language Processing(also: NLP, Computational Linguistics)

A branch of artificial intelligence that enables computers to understand, interpret, and generate human language. In accessibility, NLP powers voice-based assistive technologies, automatic captioning, text simplification for cognitive accessibility, and natural language query…

Natural Language Understanding(also: NLU, Intent Recognition, Language Understanding)

A branch of artificial intelligence that enables computers to interpret the meaning and intent behind human language input, rather than requiring exact predetermined phrases or commands. In accessibility contexts, NLU is valuable for voice-controlled interfaces because it allows…

Natural Speech Output(also: Recorded Speech, Digitized Speech)

Speech output produced from digital recordings of actual human speakers, as opposed to artificially generated synthetic speech. Natural speech output preserves the prosody, intonation, emotion, and vocal quality of the original speaker, making it generally more pleasant and…

Natural User Interface(also: NUI)

A user interface designed to feel intuitive and invisible, allowing users to interact with technology through natural behaviors such as gestures, voice, touch, or body movement rather than learned conventions like mouse clicks or keyboard commands. NUIs are particularly valuable…

NavCog(also: Navigational Cognitive Assistant)

A Bluetooth beacon-based navigation system developed at Carnegie Mellon University that provides indoor turn-by-turn navigation assistance and environmental information to blind and visually impaired users via smartphone. NavCog works by detecting BLE (Bluetooth Low Energy)…

NavTap

A navigational text-entry method designed for blind mobile phone users that reduces the cognitive load associated with inputting text without visual feedback. NavTap organizes the alphabet into five rows beginning with vowels and allows users to navigate between letters using…

Navigation

The task of moving through an environment to reach a destination, encompassing route planning, mode selection, real-time decision-making, and responding to obstacles. In accessibility research, navigation is often paired with wayfinding (the embodied, situated practice of…

Navigation Axis(also: Multi-Axial Navigation, Axis-Based Navigation)

A navigation axis is a concept from screen reader research describing a specific linear serialization of a subset of web page elements that represents one navigation strategy. Rather than forcing blind users through a single reading order (the DOM order), a multi-axial…

Navigation Robot(also: Guide Robot, Autonomous Navigation Robot)

A robotic system designed to guide users through physical spaces, providing wayfinding assistance and contextual information. In museum contexts, navigation robots can lead visually impaired visitors between exhibits, reduce the cognitive load of independent navigation, and…

Navilens

A navigation and information system that uses specially designed colorful QR-like codes that can be detected by a smartphone camera from long distances and wide angles, without requiring precise aiming. Originally developed for people with visual impairments, Navilens codes can…

Near-Miss Detection(also: Near-Miss Interaction)

A strategy for identifying when a user almost but not quite succeeds at a device interaction, suggesting they might benefit from an accessibility accommodation. For example, if a user repeatedly attempts a double-click but falls just outside the required timing threshold, the…

Nemeth Braille Code(also: Nemeth Code, Nemeth Mathematics Braille)

A system of Braille encoding developed by Abraham Nemeth in 1946 for representing mathematical and scientific notation, widely used in the United States and some other English-speaking countries. The Nemeth Code uses combinations of standard six-dot Braille cells with…

Neural Control(also: Neural Interface, Neural Signal Input)

A method of computer interaction where users modulate their brain signals, detected through electroencephalography (EEG) or other neural monitoring technologies, to generate input commands. Neural control users can typically produce a small number of distinct signals by…

Neural Prosthetics(also: Neuroprosthetics, Neural Prostheses)

Devices that interface directly with the nervous system to restore or supplement lost sensory, motor, or cognitive functions. Neural prosthetics can be input devices (reading neural signals to control external equipment, as in brain-computer interfaces) or output devices…

Neurofeedback(also: EEG Biofeedback, Neurotherapy)

Neurofeedback is a type of biofeedback that uses real-time monitoring of brain electrical activity (typically via EEG) to teach individuals to self-regulate their brain function. Users receive feedback — often through visual, audio, or game-based interfaces — about their current…

Neurotrophic Electrode(also: Neurotrophic Brain Electrode, Cone Electrode)

A type of implantable brain electrode designed for long-term, stable recording of neural signals. Unlike conventional electrodes that sit on the brain surface or are inserted as rigid probes, a neurotrophic electrode consists of a hollow glass cone coated with neurotrophic…

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 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-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-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 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 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-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…

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),…

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,…

Nonvisual Programming(also: Non-Visual Programming, Blind Programming)

The practice of writing, navigating, debugging, and managing software code without relying on visual display, typically using screen readers, braille displays, and audio cues. Nonvisual programmers face unique challenges with syntax highlighting, code indentation, error…

Note-Taking Accommodation(also: Note-Taker Service, Classroom Note-Taking Support)

An educational accommodation that provides students with disabilities access to lecture content they cannot capture independently. Traditional note-taking accommodations include human note-takers (peers or professionals who share their notes), lecture recording systems, and…

Notification Fatigue(also: Alert Fatigue, Information Overload)

Notification fatigue is a state in which users become desensitized to or overwhelmed by frequent alerts, notifications, or information delivery from a device or system, causing them to ignore or tune out important messages. In accessibility contexts, notification fatigue is a…

Novint Falcon

A consumer-grade 3D haptic input device originally marketed for gaming that has been widely adopted in accessibility research for providing force feedback to people with visual impairments. The device features a grip attached to three arms that can exert forces in three…

46 results.