Who Web Accessibility Is For: Disability Types, Assistive Tech, and the WCAG Principles That Serve Them

Visual disabilities span a wide range. People who are blind navigate with screen readers such as JAWS, NVDA, and VoiceOver, which convert the page to speech or to a refreshable Braille display. People with low vision rely on screen magnifiers, browser zoom, or a larger system font. Color vision deficiency is common, so red/green status cues used alone routinely fail.

These users depend on the structure your code exposes, not just the pixels on screen. A screen reader announces heading levels, link text, alt text, form labels, and ARIA roles, so a div styled to look like a button but missing a role is invisible as a control.

• 1.1.1 Non-text Content (A): every meaningful image needs an alt text equivalent; decorative images get an empty alt so they are skipped.
• 1.4.3 Contrast (Minimum) (AA): 4.5:1 for normal text and 3:1 for large text.
• 1.4.11 Non-text Contrast (AA): 3:1 for interactive components and meaningful graphics against adjacent colors.
• 1.4.1 Use of Color (A): never rely on color alone to convey meaning; pair it with text, an icon, or a pattern.
• 1.4.4 Resize Text (AA) and 1.4.10 Reflow (AA): content stays usable at 200% zoom and reflows to a single column at 320 CSS pixels wide.

Practical wins here include semantic headings, descriptive link text, and passing color checks. Tools like our contrast checker and alt-text checker catch the most common failures, and our guide to writing alt text covers the judgment calls.

People who are deaf or hard of hearing cannot rely on audio. They use captions, transcripts, and sign language; many also use the visual notifications and status text your interface provides instead of audio cues. Under WCAG, captions are not optional polish: they are how this audience accesses spoken content.

• 1.2.2 Captions (Prerecorded) (A): synchronized captions for recorded video with audio.
• 1.2.4 Captions (Live) (AA): captions for live streams and webinars.
• 1.2.1 Audio-only and Video-only (Prerecorded) (A) and 1.2.3 Audio Description or Media Alternative (Prerecorded) (A): an alternative so visual-only and audio-only content is also conveyed.

A common mistake is treating auto-generated captions as finished. Machine captions garble names, numbers, and technical terms, so they need a human review pass. Transcripts add a bonus: they are indexable, which is one of several places where accessibility and SEO reinforce each other.

Motor disabilities range from tremor and limited fine motor control to paralysis and repetitive strain injury. Some people cannot use a mouse at all and navigate entirely by keyboard. Others use switch devices, eye-tracking, or voice control software like Dragon, which clicks elements by their visible name. The shared requirement is that everything reachable by mouse must also work without one.

• 2.1.1 Keyboard (A): all functionality operable from the keyboard, with no traps.
• 2.4.7 Focus Visible (AA) and 2.4.11 Focus Not Obscured (Minimum) (AA, new in 2.2): the focused element is clearly visible and not hidden behind sticky headers or cookie bars.
• 2.5.7 Dragging Movements (AA, new in 2.2): any drag action has a single-pointer alternative such as tap-to-place.
• 2.5.8 Target Size (Minimum) (AA, new in 2.2): interactive targets are at least 24 by 24 CSS pixels, or have enough spacing.
• 3.3.8 Accessible Authentication (Minimum) (AA, new in 2.2): no cognitive function test like transcribing a code is required to log in, easing both motor and cognitive load.

Keyboard access is one of the highest-leverage areas to test because it is easy to verify by hand: tab through a page and confirm you can reach and operate every control while always seeing where focus is. Our guides on keyboard accessibility and visible focus indicators walk through the details.

Cognitive and learning disabilities are the largest and most varied category: dyslexia, ADHD, memory impairments, autism, and the effects of aging. There is no single assistive tool here. Instead, users rely on consistent layouts, plain language, predictable behavior, text-to-speech, and reading aids. Accessibility for this group is mostly about reducing the load your interface imposes.

• 3.2.3 Consistent Navigation (AA) and 3.2.4 Consistent Identification (AA): navigation and component naming stay consistent across pages.
• 3.2.6 Consistent Help (A, new in 2.2): help mechanisms appear in the same relative place on every page.
• 3.3.1 Error Identification (A) and 3.3.3 Error Suggestion (AA): errors are described in text and a fix is suggested, not just flagged red.
• 3.3.7 Redundant Entry (A, new in 2.2): information already entered is not demanded again in the same process.
• 1.4.12 Text Spacing (AA): content survives increased line height and letter spacing, which many reading tools apply.
• 2.2.1 Timing Adjustable (A): time limits can be extended or turned off.

Forms are where cognitive accessibility most often breaks down: vague errors, lost input after a mistake, and unlabeled fields. Our accessible forms guide covers patterns that lower friction for everyone.

The categories above describe permanent disabilities, but the same barriers hit people temporarily or situationally. A broken arm makes someone keyboard-dependent for weeks. Bright sunlight on a phone screen mimics low vision and makes contrast matter. A noisy cafe or a quiet office turns every video into a captions-only experience. Aging gradually combines reduced vision, hearing, dexterity, and memory.

This is the strongest argument for treating accessibility as baseline quality rather than a niche feature. The 24-pixel target that helps a person with tremor also helps a commuter tapping on a moving bus. Captions written for deaf users serve many viewers who watch social video with the sound off. Building for the edges makes the center more usable too.

WCAG organizes everything above under four principles, summarized as POUR. Content must be Perceivable (people can sense it, via alt text, captions, contrast), Operable (people can use it, via keyboard support and large enough targets), Understandable (predictable, plain, forgiving of mistakes), and Robust (it works with assistive tech, via valid semantics and correct ARIA). Each disability type leans on a different mix, but a usable site needs all four.

These principles also underpin the law. In the EU, the European Accessibility Act applies from 28 June 2025 and sets WCAG 2.2 Level A and AA as the baseline through the harmonized standard EN 301 549. It covers services such as e-commerce, banking, e-books, electronic communications, and self-service terminals. Whatever your jurisdiction, the WCAG criteria are the practical target. To turn principles into a worklist, start with the WCAG reference and the accessibility checklist, then scan your pages to see which user groups your site currently leaves out.