As someone who speaks conversational Japanese (well, probably more since I do banking, doctor, etc. on my own, but my grammar is far from perfect), and fluent English, Google’s AI can make some… questionable choices when translating at least. My wife (fluent Japanese speaker who knows a little English) and I decided to play with its translator function when I got a pixel phone and once again a bit latter trying to come up with some English practice for her.

Japanese is definitely a bit more difficult to work with since it’s so context-dependent and has lots of homophones (one reason translating things into Japanese and back can be interesting, particularly in the older days of Google Translate). It’s fine for short, concise, and non-complex sentences, but even certain formal grammar and honorifics can be bad with the AI translation services.