diff --git a/user.js b/user.js
index 5d4e9c5d..b8803bcd 100644
--- a/user.js
+++ b/user.js
@@ -79,9 +79,14 @@ user_pref("dom.enable_performance",				false);
 
 // Speech recognition
 // https://dvcs.w3.org/hg/speech-api/raw-file/tip/speechapi.html
+// https://developer.mozilla.org/en-US/docs/Web/API/SpeechRecognition
 // https://wiki.mozilla.org/HTML5_Speech_API
 user_pref("media.webspeech.recognition.enable",			false);
 
+// Speech synthesis
+// https://developer.mozilla.org/en-US/docs/Web/API/SpeechSynthesis
+user_pref("media.webspeech.synth.enabled", false);
+
 // Disable getUserMedia screen sharing
 // https://mozilla.github.io/webrtc-landing/gum_test.html
 user_pref("media.getusermedia.screensharing.enabled",		false);