Android: SpeechSynthesisUtterance requires lang field, even after setting voice.

[rbozan]

There's one caveat which I noticed with the API on Android, which is that the voice does not work unless the lang property is also set. You can set the lang property to the value of voice.lang and it'll work, but keeping it undefined makes voice not work at all.

[HadrienGardeur]

Thanks, that's a good catch. I'm also adding that one to the project dedicated to well-known issues. I'll also have to tweak my demo to take this into account.

You can set the lang property to the value of voice.lang and it'll work, but keeping it undefined makes voice not work at all.

Just to clarify that one, by "not work at all", do you mean that it defaults to the system default or that the playback doesn't even start at all?

[HadrienGardeur]

Also worth mentioning that HadrienGardeur/read-aloud-best-practices#6 remains an issue, in addition to setting up lang on SpeechSynthesisUtterance.

[rbozan]

Thanks, that's a good catch. I'm also adding that one to the project dedicated to well-known issues. I'll also have to tweak my demo to take this into account.

You can set the lang property to the value of voice.lang and it'll work, but keeping it undefined makes voice not work at all.

Just to clarify that one, by "not work at all", do you mean that it defaults to the system default or that the playback doesn't even start at all?

Yes I meant that it uses the system default.

What I don't understand is that its stated that voice packs must be installed for the voice to work but I don't think I have installed the voice pack and it still works.

[HadrienGardeur]

What I don't understand is that its stated that voice packs must be installed for the voice to work but I don't think I have installed the voice pack and it still works.

Voice packs are pre-loaded for a number of languages by default on Android.

[HadrienGardeur]

@rbozan I did some additional testing and you're right, something has changed on Android compared to some of my previous test.

Here's what I did:

• I uninstalled the Catalan voice pack from system settings
• I then went to my demo and selected Catalan, and it worked
• Going back to system settings, this seem to have triggered the download of the Catalan voice pack automatically
• I went back to the demo and tested again, it read the text with another voice (same voice available in system settings)

I'm running the beta version of Android 15, but this could also be related to a Chrome update. I'll need to do some additional testing, I'm mostly wondering why it fallbacks to another voice when the voice pack is uninstalled.

[rbozan]

Thanks a lot for the testing by the way, it helps me a bunch