> Is `SpeechSynthesisUtterance` prefixed in iOS7 ?

No, it's not. 

> and it isn't prefixed in Chrome Canary either

AFAIK it's not supported in Chrome Canary yet (I'm using: `Version 32.0.1655.0 canary` on Mac OS X and  `Google Chrome is up to date`). Am I missing something ? Is it behind a flag ?

> so maybe simply `'SpeechSynthesisUtterance'` in window would do the job?

For now yes.

@stucox Do you want me to make the change ?