Glossary

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ARIA Live Region(also: Live Region, ARIA Live)

An ARIA live region is a section of a web page marked with the aria-live attribute that announces dynamic content changes to assistive technologies without requiring user focus to move to the updated area. Live regions are essential for making real-time updates — such as status…

Accessibility Focus(also: A11y Focus, Screen Reader Focus)

The currently selected element in a user interface as perceived by a screen reader or other assistive technology. When an element has accessibility focus, the screen reader announces its description and the user can interact with it. Only one element can have accessibility focus…

Accessibility Tree(also: A11y Tree, Accessible Tree)

A hierarchical data structure maintained by operating systems and browsers that represents the accessible elements of a user interface in a form that assistive technologies can interpret. The accessibility tree is derived from the visual UI but organized logically rather than…

Audio Interference(also: Audio Conflict, Speech Conflict)

Audio interference in a digital accessibility context is the overlap of two or more sound streams in a user's environment such that one masks another — most commonly, auto-playing media audio on a webpage drowning out a screen reader's synthesized speech. Because most consumer…

Blindness and Low Vision(also: BLV, visual impairment, vision impairment)

Blindness and low vision (BLV) collectively describes the spectrum of significant visual impairment ranging from complete absence of sight to partial sight loss that cannot be fully corrected with standard glasses or contact lenses. The World Health Organization defines low…

ChromeVox(also: ChromeVox Classic)

ChromeVox is an open-source screen reader developed by Google, built as a Chrome browser extension and serving as the default screen reader for Chrome OS (Chromebooks). Unlike traditional screen readers that rely on operating system accessibility APIs, ChromeVox communicates…

Content Description(also: contentDescription, Android Content Description)

A text attribute on Android UI elements that provides an accessible label for screen readers like TalkBack. Content descriptions serve the same purpose as alt text on web images — they convey the meaning or function of visual elements to users who cannot see them. For…

Cursor Ambiguity(also: Cursor Position Ambiguity)

The difficulty users experience in determining the exact position of the text cursor, particularly when using screen readers on touchscreen devices. Screen readers announce the character or word at the cursor location, but users may not know whether the cursor is at the…

Data Visualization Accessibility(also: Accessible Data Visualization, Chart Accessibility, Visualization Accessibility)

The practice of designing charts, graphs, diagrams, and other visual data representations so they are perceivable, operable, and understandable by people with disabilities, particularly those who are blind or have low vision. This includes providing meaningful alternative text,…

Fire Vox(also: FireVox)

An open-source, cross-platform screen reader implemented as a Firefox browser extension, created by Charles Chen as part of the CLC-4-TTS Suite. Fire Vox was notable as one of the earliest assistive technologies to support WAI-ARIA live regions, making it a key tool in the…

Fluid Traversal(also: Fluid Navigation)

A navigation design principle for screen reader interfaces that aims to mirror the flexibility of sighted visual attention. Fluid traversal has two key properties: it should be concise (requiring minimal key presses or actions to move between parts of a representation) and…

Home Page Reader(also: IBM Home Page Reader, HPR)

A talking web browser developed by IBM Japan in the late 1990s, designed specifically for blind and low-vision users. Home Page Reader combined a web rendering engine with the ProTalker text-to-speech synthesiser and exposed navigation commands through the numeric keypad,…

Listenability(also: Auditory Readability, Speech-Output Quality)

A web-accessibility usability metric that measures how appropriate a page's rendered text is when read aloud by a screen reader or voice browser — complementary to, and distinct from, raw WCAG conformance. Listenability penalises meaningless or placeholder ALT text (such as…

Listening Rate(also: Comprehension Speed, Listening Speed)

The maximum speed at which an individual can accurately comprehend spoken or synthesized speech, typically measured as a normalized value or in words per minute. Research shows that experienced screen reader users can achieve listening rates far exceeding typical human speech…

Logical Navigation(also: Structural Navigation, Semantic Navigation)

A non-visual navigation strategy in which a user moves through a web page by its semantic structure — jumping between heading levels, ARIA landmarks, skip links, form fields, or other role-tagged regions — rather than reading the content sequentially or sampling fragments by…

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…

Navigability(also: Ease of Navigation, Web Navigability)

The ease and efficiency with which a user can move through a web page, application, or document to reach their intended content. For accessibility practice, navigability is a primary determinant of whether a screen-reader, voice-browser, or keyboard-only user can actually…

Navigation Granularity(also: Text Navigation Level, Granularity Level)

The unit of text movement when navigating through content—typically character, word, sentence, line, or paragraph level. Screen reader users must select their desired navigation granularity before moving through text, and the choice significantly affects editing efficiency.…

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…

Orca(also: GNOME Orca)

A free, open source screen reader for the GNOME desktop environment on Linux and Unix-like operating systems. Orca provides access to graphical applications through speech synthesis, braille output, and magnification. It uses the AT-SPI (Assistive Technology Service Provider…

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

Named regions of a web page that identify its high-level structure — for example banner, navigation, main, complementary, search, form, contentinfo — so that assistive technology can expose them as jump targets. Landmarks are typically declared with semantic HTML elements…

Perceptual Congruence(also: Perceptually Congruent Structure)

A design principle for accessible representations that requires the structure of a non-visual interface (such as a screen reader navigation tree) to mirror the visual structure of the original graphical representation. A perceptually congruent screen reader structure preserves…

Press-and-Listen Paradigm(also: Sequential Navigation, Linear Content Consumption)

The fundamental interaction model of screen reader assistive technology, where users press keyboard shortcuts to move through web content elements one at a time and listen to each element being announced sequentially. This paradigm transforms the two-dimensional graphical…

Reading Order(also: Logical Reading Order, Narration Order)

The sequence in which content is presented to assistive technology users, particularly screen reader users, when navigating a document or web page. For sighted users, the visual layout of a document (columns, sections, sidebars) implicitly suggests a reading flow, but screen…

Scanning Navigation(also: Non-Visual Scanning, Auditory Scanning)

A non-visual navigation strategy in which a screen-reader or voice-browser user steps rapidly through a page one fragment at a time — line by line, item by item, or in fixed jumps (e.g. page-down keys) — listening just long enough to each fragment to detect an 'information…

Screen Reader(also: Screen Reading Software)

An assistive technology application that converts digital text and interface elements into synthesized speech or braille output, enabling people who are blind or have low vision to interact with computers, smartphones, and other digital devices. Screen readers interpret the…

Screen Reader Plugin(also: Screen Reader Add-on, Screen Reader Script, Screen Reader Extension)

A small piece of code that extends or modifies the functionality of a screen reader application. Screen reader plugins can make inaccessible applications accessible, customize the screen reader's behavior for specific software, add new keyboard shortcuts, and provide additional…

Screen Reader Plugin(also: Add-on, Extension, Script)

A small piece of software that extends or modifies the functionality of a screen reader. Plugins allow users to customize their screen reader experience, make partially accessible applications more usable, add keyboard shortcuts, receive custom audio feedback, and interface with…

Screen Reader Rotor(also: VoiceOver Rotor, Rotor Control)

A virtual control in screen readers like VoiceOver that allows users to change navigation settings and access different options by performing a rotation gesture on the touchscreen. The rotor lets users switch between navigation modes (headings, links, words, characters) and…

Speech Rate(also: Speaking Rate, Articulation Rate)

The speed at which speech is produced, typically measured in words per minute (WPM) or syllables per second. Normal conversational speech ranges from 120-180 WPM, while screen reader users often configure synthetic speech at rates of 300-400 WPM or higher. Speech rate settings…

Structural Navigation(also: Structure-Based Navigation)

A mode of screen reader navigation that allows users to move through content based on its logical or semantic structure rather than reading linearly from beginning to end. In web content, structural navigation involves jumping between headings, landmarks, lists, and other HTML…

Synthetic Speech(also: Artificial Speech, Computer-generated Speech)

Speech that is artificially produced by computer systems rather than recorded from human speakers. Synthetic speech is the output of text-to-speech systems and is fundamental to screen readers and voice assistants. Modern synthetic speech uses various generation methods…

System Access(also: SA, System Access to Go, SA To Go)

A screen reader for Windows developed by Serotek Corporation that was notable for offering a free version and a portable "To Go" edition that could run from a USB drive without installation. System Access was designed to provide an affordable alternative to commercial screen…

Talking Browser(also: Talking Web Browser, Speaking Browser)

A historical term for a specialised web browser that converts on-screen content into synthesised speech, enabling blind and low-vision users to browse the web through audio rather than through a separate screen reader layered over a visual browser. Talking browsers such as IBM…

Text Alternatives(also: Text Alternative, Text Equivalent)

WCAG 2.1 Guideline 1.1 and success criterion 1.1.1 require that all non-text content (images, charts, audio, video, form controls, etc.) have a text alternative serving the equivalent purpose. Text alternatives can be presented as alt text on an image, an aria-label on a…

Time-compressed Speech(also: Accelerated Speech, Speed-altered Speech)

Speech that has been digitally processed to play at a faster rate than it was originally recorded or synthesized, while preserving pitch. Unlike simply increasing playback speed (which raises pitch), time compression algorithms remove small portions of the audio signal to reduce…

Verbosity Level(also: Verbosity Setting, Detail Level)

A configurable setting that controls the amount of detail provided in text or audio descriptions of content, particularly for screen reader users and accessible data visualizations. Verbosity levels typically range from low (minimal summary with key points only) to high…

Voice Usability(also: Auditory Usability, Non-Visual Web Usability)

The degree to which a web page, application, or document is usable when accessed through a voice browser or screen reader — the audio-first counterpart to traditional visual usability. Voice usability combines structural quality (navigability — how quickly a user can reach…

VoxLens

An open-source JavaScript plug-in developed at the University of Washington that improves the accessibility of online data visualizations for screen-reader users through a multimodal approach. VoxLens provides three interaction modes: a Question-and-Answer mode where users can…

Words Per Minute(also: WPM)

A standard measure of speech or reading speed, representing the number of words produced or comprehended in one minute. Typical human speech occurs at 120-180 WPM, average reading speed is 200-250 WPM, while experienced screen reader users can comprehend synthesized speech at…

contentDescription(also: content description, android:contentDescription)

An Android accessibility attribute that provides a text description for UI elements, particularly those without visible text such as ImageButtons and ImageViews. When set, TalkBack and other Android screen readers announce this description to users. For elements that rely solely…

41 results.