The film Arrival is concerned heavily with language and translation, but as far as I can remember two things are not translated for the audience.
The first one is the circle symbol traced by the main protagonist and the Heptapod.
The second is the last words of General Shang's wife.
What is the translation of those moments?
I expect both moments to be full of meaning, so not putting any subtitles at those moments (even in VOST versions) is probably a choice from the director. But since we probably can translate them (several Heptapod symbols have translation, and Mandarin is a known language), my guess is that they offer some kind of second read on the movie.