WCAG Guideline 1.2.9: Audio-only (Live) Explained
Estimated read time: 8–10 minutes
Guideline 1: Perceivable
The first principle of WCAG, Perceivable, ensures that information and user interface components must be presented to users in ways they can perceive. This means content can’t be invisible to all of a user’s senses—whether they are seeing, hearing, or feeling the content through assistive technology.
Guideline 1.2: Time-based Media
Guideline 1.2 focuses on making time-based media—like audio and video—accessible to everyone. This includes providing alternatives such as transcripts, captions, and audio descriptions so users with different abilities can access the content.
What Is Guideline 1.2.9 Audio-only (Live)?
"An alternative for time-based media that presents equivalent information for live audio-only content is provided."
Guideline 1.2.9 is a Level AAA requirement in the Web Content Accessibility Guidelines (WCAG) .
- All live audio-only content (like radio broadcasts or live podcasts) should have a real-time text alternative, such as live captions or a transcript.
- This ensures users who are deaf or hard of hearing can access the information as it happens.
- The alternative should be as accurate and timely as possible.
This ensures that everyone can participate in live audio events, regardless of hearing ability.
Why Does It Matter?
- Inclusivity: Real-time text alternatives make live audio accessible to users who are deaf or hard of hearing.
- Legal Compliance: This is a Level AAA requirement in WCAG 2.2.
- Usability: Helps users in noisy environments or when audio can’t be played aloud.
For more, see W3C's live audio accessibility docs .
What Needs a Live Audio Alternative?
- Live radio broadcasts
- Live podcasts
- Any live audio-only event
All such content should have a real-time text alternative available.
How to Provide a Live Audio Alternative
- Use real-time captioning services or software
- Provide a live transcript or summary as the event happens
- Make the alternative easy to access and read
- Ensure captions are as accurate and timely as possible
For more, see W3C's live audio accessibility docs .
Common Mistakes to Avoid
- No real-time text alternative for live audio
- Captions that are delayed or inaccurate
- Not making the alternative easy to find
- Not testing with users or assistive technology
Audit your site regularly and use accessibility checkers to ensure all live audio content has proper alternatives. For more, see University of Washington's Live Captions accessibility guide .
Differences Between A, AA, and AAA for Guideline 1.2.9 in WCAG 2.2
- Level A: No requirement for 1.2.9.
- Level AA: No requirement for 1.2.9.
- Level AAA: Requires a real-time text alternative for all live audio-only content. This is the core requirement for 1.2.9 and is mandatory for AAA conformance.
For more, see the W3C’s official documentation for 1.2.9 Audio-only (Live) .
Quick Checklist
- All live audio-only content has a real-time text alternative
- Captions or transcripts are accurate and timely
- Alternative is easy to access and read
- Tested with users and assistive technology
- Service is reliable for the duration of the event
Summary
Guideline 1.2.9 is essential for making live audio content accessible to users who require text alternatives. By providing real-time captions or transcripts, you support users with disabilities, improve usability, and meet AAA requirements. Make live accessibility a standard part of your event planning for maximum inclusion.