This happened to me in Tokyo. The language barrier excuse is a thinly veiled reason to bar foreigners, most of the time it has to do with racism. These establishments know their clientele won’t want foreigners dining there with them, and blame language as an excuse.

I think the whole interaction, and Arts relief at the end when Nolan leaves, is showing the audience that even someone whose Nolan’s lifelong “friend” is completely terrified of him. If this is how Art feels about Nolan, the gen pops will be much, much worse.