Is the translation from English done automatically?

The translation is left up to the user so it must be done prior to calling the API.

You can find documentation here: Speech Synthesis Markup Language (SSML) Reference | Resemble AI

You can use Speech Synthesis Markup Language (your SSML) as input to control how Resemble generates speech. Resemble automatically handles normal punctation, such as pausing after a period, or speaking a sentence that ends with a question mark as a question. However, in some cases, you may want additional control of Resemble’s synthetic speech.

This may include, for example: having certain words pronounced in a specific way, saying a word or sentence with excitement, spelling certain words character by character, and much more.