Yet another Reddit refugee here, looking for something fresh.

I'm a lurker at heart, so I'll probably keep myself to myself for a bit and try to learn the ropes by example, but I do have a couple questions: first, does anyone know the exact length/character restrictions on usernames here? I was aiming for something along the lines of "Petronius the Arbiter", after the cat in the Heinlein novel, but all the variations I tried including the full words "Petronius" and/or "arbiter" were rejected as too long, and I couldn't find anything on it in the FAQ. Not that I really mind "having" to go with PeteTheCat instead, I'm just curious.

Speaking of the FAQ, I noticed that the downvoting guidelines included Snaps not in English. Some of the communities I enjoyed on reddit were subs dedicated to helping people learn new languages, and it wasn't uncommon for links/posts/etc to be in the target language. Does that mean such communities are discouraged here, or is there some wiggle room?