If it's that good with Japanese, I'd love to see it support Korean! Keeping up conversational practice is very tough as a non-native speaking not living in Korea anymore. So having an AI that I can bother at my convenience would be amazing.
i've watched enough wuxia/xianxia now to recognize about 10% of the mandarin words/phrases, but have almost no understanding of the grammar. the real key to learning seems to be (going through the often frustrating process of) communicating in real time, not just reading and listening.