WCAG (Web Content Accessibility Guidelines)

Q: "What is WCAG?"

"WCAG stands for Web Content Accessibility Guidelines. It is an international standard published by the W3C that defines how to make web content accessible to people with disabilities, including those with visual, auditory, motor, and cognitive impairments."

Q: "What are the WCAG conformance levels?"

"WCAG defines three conformance levels: A (minimum), AA (mid-range, required by most legislation), and AAA (highest). Level AA is the baseline required by the European Accessibility Act and most national accessibility laws."

Q: "What does POUR stand for in WCAG?"

"POUR stands for Perceivable, Operable, Understandable, and Robust. These are the four principles that organize all WCAG success criteria. Content must be perceivable by all senses, operable by all input methods, understandable in language and navigation, and robust enough to work with assistive technologies."

Q: "What is the difference between WCAG 2.1 and WCAG 2.2?"

"WCAG 2.2, published in October 2023, adds nine new success criteria to WCAG 2.1, including requirements for focus appearance, dragging movements, and consistent help. WCAG 2.2 is backwards-compatible with 2.1."

Q: "How does WCAG relate to the EAA?"

"The European Accessibility Act references EN 301 549, which maps to WCAG 2.1 Level AA for websites and digital interfaces. Organizations targeting EAA compliance must meet at minimum WCAG 2.1 AA requirements."

The Web Content Accessibility Guidelines (WCAG) are an international standard developed by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C). WCAG defines testable success criteria for making web content accessible to people with disabilities, including blindness, low vision, deafness, hearing loss, motor impairments, speech disabilities, photosensitivity, and cognitive limitations.

WCAG 1.0 was published in 1999. WCAG 2.0 followed in 2008, introducing the POUR framework that remains the foundation of the current standard. WCAG 2.1 (June 2018) added criteria for mobile accessibility and cognitive disabilities. WCAG 2.2 (October 2023) added nine more criteria. WCAG 3.0 is in working draft as of March 2026 and introduces a scoring model rather than pass/fail conformance levels.

Why it matters

WCAG is the technical foundation of nearly every accessibility law worldwide. The European Accessibility Act references it via EN 301 549. Section 508 in the United States, the Accessibility for Ontarians with Disabilities Act in Canada, and the UK Equality Act all point to WCAG as the compliance baseline.

For TTS implementations specifically, six WCAG criteria directly govern how audio must be delivered, controlled, and made accessible. Missing any of them creates a documentable compliance failure under the EAA.

The POUR framework

All WCAG success criteria are organized under four principles:

Perceivable. Content must be presentable in ways all users can perceive: text alternatives for images, captions for video, transcripts for audio, sufficient color contrast.
Operable. Interfaces must work without a mouse. Full keyboard navigation, no keyboard traps, sufficient time limits, no seizure-inducing content.
Understandable. Language is declared, navigation is consistent, error messages explain how to fix the problem.
Robust. Markup is valid and compatible with current and future assistive technologies, including screen readers and voice control software.

Conformance levels

Level	Meaning	Required by law?
A	Minimum accessibility	Yes, as part of AA
AA	Mid-range, addresses most common barriers	Yes (EAA, Section 508, most national laws)
AAA	Highest, not always achievable for all content	Recommended, not legally required

WCAG and TTS

Six WCAG criteria apply directly to TTS implementations:

1.4.2 Audio Control (A): audio over 3 seconds must have pause, stop, and volume controls.
1.2.1 Audio-only (A): pre-recorded audio needs a text alternative.
1.3.1 Info and Relationships (A): the audio player must be programmatically linked to its source text.
4.1.2 Name, Role, Value (A): all player controls need accessible names and ARIA roles.
2.1.1 Keyboard (A): all player functions must work via keyboard alone.
3.1.1 / 3.1.2 Language (A/AA): correct lang attributes for TTS engine pronunciation.

See the EAA Voice Accessibility Guide for detailed implementation guidance.

Frequently Asked Questions

What is WCAG?

WCAG stands for Web Content Accessibility Guidelines. It is an international standard published by the W3C that defines how to make web content accessible to people with disabilities, including those with visual, auditory, motor, and cognitive impairments.

What are the WCAG conformance levels?

WCAG defines three conformance levels: A (minimum), AA (mid-range, required by most legislation), and AAA (highest). Level AA is the baseline required by the European Accessibility Act and most national accessibility laws.

What does POUR stand for in WCAG?

POUR stands for Perceivable, Operable, Understandable, and Robust. These are the four principles that organize all WCAG success criteria. Content must be perceivable by all senses, operable by all input methods, understandable in language and navigation, and robust enough to work with assistive technologies.

What is the difference between WCAG 2.1 and WCAG 2.2?

WCAG 2.2, published in October 2023, adds nine new success criteria to WCAG 2.1, including requirements for focus appearance, dragging movements, and consistent help. WCAG 2.2 is backwards-compatible with 2.1.

How does WCAG relate to the EAA?

The European Accessibility Act references EN 301 549, which maps to WCAG 2.1 Level AA for websites and digital interfaces. Organizations targeting EAA compliance must meet at minimum WCAG 2.1 AA requirements.