On iOS 14, speechSynthesis.getVoices() returns SpeechSynthesisVoices with empty "name" attribute. speechSynthesis.getVoices().forEach(v => console.log(v.name)); This issue does not occur on iOS 13 and desktop safari 13.
<rdar://problem/69118246>
The fix for this issue was needed outside the WebKit project, therefore this is being resolved as 'Moved'. This should now be fixed in shipping software. This was fixed in iOS 14.2