Hi Michelle, we use ElevenLabs for our AI text-to-speech voices and are currently using the Multilingual v2 model which supports the languages you listed above. According to their documentation, these voices can be used to generate audio in any of the languages, even though they are listed with an American accent. It also states that they're working to provide a granular overview of how each default voice sounds in each of the languages and will update that page when it's ready. They currently don't support Thai, but they do support Vietnamese using a different model (Turbo v2.5) which we are not using because it values generation speed over accuracy. But I will note this request as we consider switching to the Turbo v2.5 model or supporting multiple models in the near future.