Text-to-Speech for Web Accessibility: Implementation Guide

Web Speech API Fundamentals

The Web Speech API's SpeechSynthesis interface is available in all modern browsers. Create an utterance, configure rate (0.5-2.0), pitch (0-2), and volume (0-1), then call speechSynthesis.speak(). Voices are platform-dependent: Chrome uses Microsoft/Google voices, Safari uses macOS neural voices, and Firefox uses system voices. Test across browsers because the same utterance sounds different on each platform.

SSML for Fine-Grained Control

SSML (Speech Synthesis Markup Language) allows prosodic control: for pauses, for emphasis, for rate changes, and for custom pronunciation. Use SSML when you need to read numbers as dates ("2026" vs "two thousand twenty-six"), spell acronyms ("API" as "A-P-I"), or control the rhythm of complex sentences.

ARIA and Screen Reader Considerations

For accessibility features built with TTS, use aria-live="polite" for non-critical announcements and aria-live="assertive" for urgent messages (like errors or timer warnings). Test with actual screen readers (NVDA, JAWS, VoiceOver) because their TTS engines differ from browser SpeechSynthesis. Our tool helps you preview the spoken form of UI copy before deployment.