I have a question about Bing Text to Speech API.
There are lots of supported voices at Supported locales and voice fonts.
Some voice names have suffixes like ", Apollo" or "RUS". It would be great if you let me know what do they mean?
Thanks in advance.
I get answer from Azure product team.
RUS indicates models based on the concatenative synthesis technology, which is normally higher fidelity, more natural and slightly bigger latency.
Apollo is just an internal service tag and customers can simply ignore that.
Update:
Ignore that means that you don't need to care about the mean of 'Apollo'. But still need to use (tja-JP, Ayumi, Apollo).
