Speech Synthesis API not working in Firefox on Manjaro

Question

I installed speech-dispatcher which works on the command line but not in firefox.

The voices array in firefox is empty.

I installed speech-dispatcher and festival

var msg = new SpeechSynthesisUtterance();
msg.text = "Good Morning"

window.speechSynthesis.speak(msg);

speechSynthesis.getVoices() // empty array

If I type: espeak "hello" it works in command line but not firefox.