Hello,
you can look up the complete list from here: https://learn.microsoft.com/en-us/azure/cognitive-services/speech-service/language-support?tabs=tts#voice-styles-and-roles.
If you want to create a list automatically, please look here: https://learn.microsoft.com/en-us/azure/cognitive-services/speech-service/rest-text-to-speech?tabs=streaming#get-a-list-of-voices
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