Glossary

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Laddering Method(also: Laddering Technique, Laddering Interview)

A qualitative-quantitative research method used in user experience research to understand why users value certain product features. Rooted in Means-End theory, the technique involves asking participants what they liked or disliked about an experience, then probing with follow-up…

Lambda Notation(also: Lambda Math Code, Lambda Braille)

A mathematical Braille notation system developed as part of the Lambda project, designed specifically for use with computers and digital documents. Lambda is an XML-based code built on a completely new foundation, featuring a Braille character dictionary and pattern-matching…

Landmark(also: Navigation Landmark, Environmental Landmark)

A distinctive environmental feature used as a reference point during navigation and wayfinding. In Orientation and Mobility training for people with visual impairments, landmarks are categorized by the sense used to detect them: structural landmarks (doors, stairs, elevators)…

Landmark Detection(also: Acoustic Landmark Detection, Stevens Landmark Theory)

Landmark detection is a speech analysis method based on Kenneth Stevens' acoustic model of speech production, which identifies perceptually significant points in the acoustic signal where listeners extract information about underlying distinctive features. Three primary landmark…

Landmark Extraction(also: Keypoint Detection, Skeletal Tracking)

A computer vision technique that identifies and tracks specific anatomical points (landmarks or keypoints) on the human body, hands, and face from images or video. In sign language technology, landmark extraction is a critical preprocessing step that converts raw video into…

Landmark Knowledge

A type of spatial knowledge involving the recognition and memory of distinctive features or objects in an environment that serve as reference points for navigation. Landmarks are fixed objects at specific locations—such as a doorway, a change in floor material, or a particular…

Landmark Navigation(also: Navigate by Landmarks, ARIA Landmark Navigation)

A screen reader navigation strategy that allows users to jump between major structural regions of a webpage defined by ARIA landmark roles (banner, navigation, main, complementary, contentinfo, search, form) or their equivalent HTML5 semantic elements. Landmark navigation…

Landmark Object(also: Navigation landmark, Target object)

A specific physical object that serves as the terminal target of a navigation task — for example, an empty chair in a waiting area, a push-button at an elevator, a ticket barrier, a door handle, or a counter at a shop. For blind travellers, landmark objects are the object of…

Landmark Theory(also: Stevens Landmark Theory)

A theoretical framework in speech science developed by Kenneth N. Stevens proposing that listeners extract phonetic information from acoustically abrupt events called landmarks in the speech signal. Landmarks mark points of rapid spectral change — such as the release of a stop…

Landmark-Based Navigation(also: Landmark Navigation, Landmark-Based Wayfinding)

A wayfinding strategy that uses recognisable environmental features such as buildings, signs, or other prominent objects as reference points for giving directions, rather than relying solely on street names or turn-by-turn instructions. Research has shown that landmark-based…

Landmarks(also: ARIA Landmarks, Page Landmarks, Landmark Regions)

Designated regions of a web page that provide structural navigation points for assistive technology users. ARIA landmark roles include banner, navigation, main, complementary, contentinfo, search, form, and region. Screen reader users can jump between landmarks using keyboard…

Language Access(also: Language Services, Linguistic Access)

The provision of services and resources that enable people with limited proficiency in the dominant language to meaningfully access information, programmes, and services. Language access encompasses professional interpretation (spoken), translation (written), bilingual staffing,…

Language Accessibility(also: Linguistic Accessibility)

The practice of ensuring that information, services, and digital content are available and comprehensible in the languages that people actually use and prefer. Language accessibility extends beyond translation between spoken languages to include providing content in signed…

Language Acquisition(also: Language Development, Language Learning)

The process by which humans develop the ability to perceive, produce, and use language to communicate. In deaf children, language acquisition presents unique challenges: 90% of deaf children are born to hearing parents, and without early exposure to an accessible language (such…

Language Deprivation(also: Linguistic Deprivation)

The condition that occurs when children do not receive sufficient accessible language input during critical developmental periods, leading to atypical neural development, cognitive delays, and lifelong mental health challenges. DHH children in hearing families who do not use…

Language Erasure(also: Linguistic Erasure, Language Flattening)

The process by which a language's unique characteristics, variations, dialects, and cultural significance are diminished, homogenized, or eliminated — often through the dominance of a majority language or through technologies that oversimplify linguistic complexity. In the…

Language Immersion

An approach to language learning in which the learner is surrounded by and continuously exposed to the target language in natural, meaningful contexts rather than through isolated instruction. In the context of deaf education and accessibility, language immersion is critical…

Language Impairment(also: Language Disorder, Language Disability)

A reduced ability to understand or produce spoken, written, or signed language that is not due to hearing loss, intellectual disability, or lack of exposure to language. Language impairments can be developmental (present from childhood) or acquired (resulting from brain injury…

Language Justice(also: Linguistic Justice)

A framework that advocates for the equal valuing and inclusion of all languages in social, educational, and technological contexts, challenging the dominance of English and other majority languages. In accessibility research, language justice highlights how reading support…

Language Localization(also: L10N, Localization)

The process of adapting a product, application, or content for a specific language, culture, and region, including translation, cultural adaptation of imagery and symbols, currency and date formats, and text-to-speech voice support. Language localization is a critical barrier…

Language Model(also: Statistical Language Model, LM)

A computational model that assigns probabilities to sequences of words, enabling prediction of likely next words or sentences in text. In assistive technology, language models power word and sentence prediction systems by learning patterns from training corpora. Modern AAC…

Language Remediation(also: Language Therapy, Language Intervention)

Language remediation is the process of treating language disorders through structured intervention designed to improve a person's ability to understand and produce language. In the context of accessibility and assistive technology, language remediation often involves…

Language Understanding Intelligent Service(also: LUIS, Azure LUIS)

A cloud-based Microsoft Azure service that applies machine learning to natural language text to predict meaning and extract relevant information. LUIS identifies user intents (what they want to do) and entities (key information in their utterance). In accessibility applications,…

Language-Based Learning Impairment(also: LLI, Language Learning Impairment, Language Learning Disability)

A developmental condition in which children have difficulty acquiring language and later reading skills while other cognitive abilities appear relatively intact. Language-based learning impairments affect an estimated 20% of preschool and school-aged children, and more than 50%…

Languaging

A sociolinguistic concept that reframes language as an ongoing activity rather than a fixed system. Developed by scholars including Alastair Pennycook and Li Wei, languaging treats communication as the dynamic use of all available linguistic and semiotic resources — words,…

Langue des Signes Québécoise(also: LSQ, Quebec Sign Language)

The sign language used by the Deaf community in francophone Quebec and in francophone Deaf communities elsewhere in Canada. LSQ is a distinct natural language with its own grammar, lexicon, and cultural tradition — not a signed version of French — and developed historically from…

Large Language Model(also: LLM)

A type of artificial intelligence model trained on vast amounts of text data to understand and generate human language. Large language models like GPT-4, Claude, and Gemini power many generative AI applications. In accessibility contexts, LLMs enable natural language interfaces…

Large Language Models(also: LLMs, foundation models)

Large language models are AI systems trained on vast corpora of text data using transformer-based neural network architectures, enabling them to generate, summarize, translate, and reason about natural language. In accessibility contexts, LLMs power conversational assistants…

Large Print(also: Large Type, Enlarged Print, Giant Print)

Text or graphic material produced in a larger-than-standard font size to improve readability for people with low vision. Large print typically uses font sizes of 16 to 18 points or larger, though individual needs vary significantly depending on the type and degree of vision…

Large Print Music(also: Enlarged Music, Large Print Notation)

Music notation that has been enlarged from standard size to improve readability for musicians with low vision. Large print music is typically created by photocopying or printing scores onto A3 or tabloid-sized paper, or by digitally enlarging PDF files. While quicker and cheaper…

Large Vision Model(also: LVM)

A large vision model is a foundation model trained on very large image (and often video) datasets to produce general-purpose visual representations - capable of object detection, segmentation, captioning, or feature extraction without task-specific retraining. Examples include…

Large multimodal model(also: LMM, Multimodal AI, Vision-language model)

An artificial intelligence model capable of processing and generating content across multiple modalities, such as text, images, and audio. Examples include GPT-4V and Gemini. In accessibility applications, large multimodal models enable powerful new capabilities like generating…

Large-Print Notation(also: Large-Print Music, Enlarged Music Notation)

Sheet music that has been enlarged or reformatted with larger symbols and staves to improve readability for people with low vision. Large-print music notation requires a specialized conversion process and is available from only a few sources, such as select libraries. While…

Large-Scale Web Accessibility Evaluation(also: Large-Scale Accessibility Assessment, Web Accessibility Survey)

The systematic automated or semi-automated assessment of web accessibility across hundreds or thousands of websites to understand broad trends, compliance rates, and the overall state of accessibility on the web. These evaluations typically use automated testing tools like…

Laryngectomy(also: Total Laryngectomy)

The surgical removal of the larynx (voice box), typically performed as treatment for advanced laryngeal or throat cancer. A total laryngectomy results in the permanent loss of the natural voice, as the vocal folds that produce speech are removed. The airway is also permanently…

Laryngectomy(also: Larynx Removal, Voice Box Removal)

A surgical procedure to remove all or part of the larynx (voice box), most commonly performed as treatment for laryngeal cancer. Total laryngectomy removes the entire larynx and separates the airway from the mouth, nose, and esophagus, requiring the person (called a…

Laser Cutter(also: CO2 Laser Cutter)

A digital fabrication machine that uses a focused laser beam to cut or engrave flat materials such as wood, acrylic, cardboard, leather, and some plastics. Along with 3D printers and CNC routers, laser cutters are a core tool in makerspaces and community fabrication labs, and…

Last Meter Problem(also: Last Mile Problem, Final Approach Problem)

In assistive technology for blind users, the challenge of bridging the gap between knowing an object exists and physically reaching or interacting with it. While object detection apps can identify what objects are present and approximately where they are, they typically cannot…

Last-Few-Meters Problem(also: Last 10 Meters Problem, Last Mile Problem (Navigation))

The navigation challenge that occurs when GPS or other positioning systems bring a person with a visual impairment to the general vicinity of their destination (typically within 5-10 meters) but cannot guide them to the precise location, such as a specific entrance, storefront,…

Last-Few-Metres Problem(also: Last Few Meters Problem)

The difficulty that blind and low-vision pedestrians face in the final short distance (roughly the last several metres) of a trip, where GPS accuracy degrades, building entrances are ambiguous, and digital navigation apps leave users in the general vicinity of a destination…

Last-few-meters Wayfinding(also: Last-meter wayfinding, Last-few-meters problem)

The final segment of an indoor or outdoor journey, from the nearest routable point (a building lobby, a doorway, a kerbside pin on a map) to the exact end destination (a specific room, counter, or seat). For blind travellers, this last segment is disproportionately difficult:…

Late Blind(also: Adventitiously Blind, Acquired Blindness)

A person who lost their vision later in life, typically after age 5-7 when visual memories and concepts have been established. Late blind individuals often retain visual memories and may use these to construct mental representations of spaces and routes. Research suggests late…

Late Deafened(also: Adventitiously Deaf, Acquired Deafness)

Late deafened refers to individuals who became deaf after developing spoken language, typically in adolescence or adulthood. Unlike people who are born deaf or become deaf in early childhood, late-deafened individuals often grew up in hearing culture with spoken language as…

Late Diagnosis(also: Adult Diagnosis, Delayed Diagnosis)

Receiving a formal diagnosis of a condition significantly later than when symptoms first appeared, often in adulthood for conditions typically identified in childhood. Late diagnosis of ADHD and autism is common, particularly among women, people of color, and those who developed…

Late binding

A software engineering concept where decisions about how components connect are deferred until runtime rather than being fixed at design time or compile time. In user interface design, late binding refers to the practice of keeping the abstract description of an interface…

Late-Life Disability(also: Age-Related Disability, Acquired Age-Related Disability)

Disability that develops gradually as a person ages, including changes in vision, hearing, motor control, and cognition. Unlike disabilities present from birth or acquired through injury, late-life disabilities often develop incrementally, and individuals may not identify as…

Latency(also: Delay, Lag, Response Time)

The time delay between when an event occurs and when its accessible representation is delivered to the user. In real-time captioning, latency is the gap between spoken words and their appearance as text, typically measured in seconds. In screen readers and other assistive…

Latent Semantic Analysis(also: LSA, Latent Semantic Indexing, LSI)

A natural language processing technique that uses mathematical methods (Singular Value Decomposition) to identify patterns in relationships between words and concepts within a large corpus of text. In accessibility applications, LSA enables context-aware word prediction by…

Laterality(also: Left-Right Discrimination, Lateral Awareness)

Laterality is the ability to distinguish between left and right sides of the body and to apply this understanding to the surrounding environment for spatial orientation and navigation. Laterality is a fundamental spatial cognition skill that underpins many daily activities, from…

Latin Square Design(also: Latin Square Counterbalancing)

A counterbalancing method used in experimental research to control for order and sequence effects when each participant experiences multiple conditions. In a Latin Square arrangement, conditions are ordered so that each condition appears in each position (first, second, third,…