I’m also highly interested in Mandarin subtitles. I obviously don’t know how your app works, but I don’t think it’s an issue the translation API should solve. As fwouts mentioned before, you could use a Javascript module to get from the Chinese translation to Pinyin. For example, the first result from google https://www.npmjs.com/package/chinese-to-pinyin enables you to do: pinyin(“今天天气真好”) returns “jīn tiān tiān qì zhēn hǎo”. I’d be happy to help to make this work.