The newest MS Edge supports the text to speech API & all tests pass. However, the fluid.textToSpeech.checkTTSSupport function that gates the test runs incorrectly reports Edge doesn't support TTS (I removed it locally to check).
The issue seems to be twofold:
- MS Edge won't actually speak if SpeechSynthesisUtterance is given an empty string
- fluid.promise has slow performance on MS Edge & takes more than the default 1 second to return
A small patch is incoming for this issue that will make the TTS wrapper work in Edge.