WCAG 1.2.9 Audio-only (Live): How to Provide Live Audio Alternatives

What This Criterion Requires

WCAG 1.2.9 Audio-only (Live) is a Level AAA success criterion that requires an alternative for time-based media to be provided for any live audio-only content. This includes live podcasts, internet radio broadcasts, audio-only webinars, conference call recordings streamed in real time, and audio announcements. Unlike the Level A requirement for prerecorded audio, this criterion specifically addresses the harder problem of synchronously available text for live audio. The most common solution is real-time captioning through a Communication Access Realtime Translation (CART) provider, automated speech-to-text services, or a live transcript fed directly into the page. Because live captioning is technically demanding and expensive, this criterion sits at Level AAA, but it remains essential for organizations that broadcast frequently to deaf or hard-of-hearing audiences and for any public sector body that streams audio meetings.

Why It Matters

An estimated 466 million people worldwide have disabling hearing loss, and live audio is one of the few content types they cannot access on their own schedule. Without a synchronous text alternative, deaf and hard-of-hearing users are completely excluded from live podcasts, town halls, investor calls, religious services, and emergency announcements at the moment they happen. Live captions also benefit users in noisy environments, non-native speakers who read more easily than they listen, and users who cannot turn audio on at work or in libraries. For public-sector organizations subject to the European Accessibility Act or Section 508, failing to caption live audio creates direct legal exposure. Even private organizations face reputational damage when high-profile live events exclude disabled audiences, as several streaming platforms have learned through public backlash.

Common Failures and How to Fix Them

<audio controls>
  <source src="https://stream.example.com/live" type="audio/mpeg">
</audio>
<!-- No live transcript area, no CART link, no captions iframe -->

<audio controls aria-describedby="live-transcript">
  <source src="https://stream.example.com/live" type="audio/mpeg">
</audio>
<section id="live-transcript" aria-live="polite" aria-atomic="false">
  <h2>Live transcript</h2>
  <p>Captions appear here in real time, provided by a CART writer.</p>
</section>

<iframe src="https://audio-conf.example/room/42" title="Live town hall"></iframe>

<iframe src="https://audio-conf.example/room/42" title="Live town hall"></iframe>
<p>
  <a href="https://captions.example/room/42" target="_blank" rel="noopener">
    Open live captions in a new window (provided by Streamtext)
  </a>
</p>

// Player init with captions disabled
livePlayer.init({
  source: 'rtmp://stream.example.com/live',
  captions: { enabled: false }
});

// Enable ASR captions and surface the CC control
livePlayer.init({
  source: 'rtmp://stream.example.com/live',
  captions: {
    enabled: true,
    provider: 'asr',
    language: 'en-US',
    showControl: true
  }
});

How to Test

1. Open the live audio page during an actual broadcast and confirm that synchronized text is visibly available without requiring the user to leave the page or install extra software.
2. Verify that the captioning channel updates in real time, not after the broadcast ends; a delay of more than a few seconds is acceptable, but a delay of minutes effectively fails the criterion.
3. Check that the live transcript region uses an aria-live polite announcement so screen reader users with residual hearing can follow along, and that the region is keyboard-focusable.
4. Confirm that the audio player exposes the captions control, and that turning captions on or off does not interrupt the audio stream.

CMS-Specific Guidance

This criterion commonly causes issues on these platforms:

• Wordpress Accessibility Checklist
• Squarespace Accessibility Checklist
• Wix Accessibility Checklist

Further Reading

• Video Accessibility Captions Guide
• Accessible Events Webinars Guide
• Wcag Explained Plain English

Related WCAG Criteria

• WCAG 1.2.4
• WCAG 1.2.2
• WCAG 1.2.1