#heartspeak

I think he can speak literally any language!

Balan, Lance and any other member of the Maestro species can understand and speak any language they encounter, to various degrees. This is due to the fact Maestros don't necessarily speak through regular means! Most, if not all Maestro's have an ability called 'Heartspeak', where they can create an instantaneous connection from their heart straight to another's. This allows them to completely read a person right from a first glance -they'll read their story, they'll understand their current reason for being unbalanced (if they first meet in the Theatre, that is), and even little details that can help them understand exactly what they need to have their balance repaired.

It also makes sense that Balan and Lance would have a pretty strong set of linguistic skills because they've been around for SO long, and have encountered millions of people multiple times, which would constantly keep their skills sharp even if they didn't have the ability of Heartspeak.

They have also taught themselves sign language for inclusivity, and in fact, when Balan or Lance create copies of themselves their dopplegangers actually don't have the ability to speak with a voice, so they all use sign language instead!