I\'m using the speech synthesis API on Android-Chrome. The issue is that although there are 4 English voices available, it is always US English that is used by the browser,
The only way to work around this issue on Android version 5.0.2 is to change the default voice in the Android settings and then restart the device. That will let you use the voice you want, but the other English ones will then be unavailable. Here is some more detail:
SpeechSynthesis.getVoices() will return several options for English (United States, Australia, Nigeria, India, and United Kingdom) but only one is available at a time. You can pick which one by going to the Settings app, then Controls->Language and input->Text-to-speech options. Select the gear icon next to Google Text-to-speech Engine, then under Language you can update the exact locale you want to use. If you select "Install voice data" you can even select from a sample of different voices for some locales. You need to restart the device after changing this setting for it to take effect.
The voice used on an Android device when you play a SpeechSynthesisUtterance will depend on what you have selected in the Android settings. You can choose which language you want to play from javascript (see below for details) but you have no control over the locale or exact voice used.
This problem occurs on Chrome and Firefox, so it is likely a problem with the Android platform's implementation of the speechSynthesis API. It's unlikely that a browser update will fix this, but different versions of Android might. (My test device is on Android 5.0.2, so if this is fixed in a future update, please let me know).