Which Language Are They Speaking in the Various Parts of JoJo?

[Papasmurf]

For parts like 1, 4, 5, 6, 7 and 8 we can pretty easily assume they are just speaking the language of the country in which the entirety of the parts are taking place in, but what about the others? Which language do you think they spoke in Battle Tendency and Stardust Crusaders, where they change settings multiple times?

In Battle Tendency I would probably say Joseph primarily spoke English throughout the part, but Stroheim likely alternated between speaking German, Spanish, Italian and English due to conversing with Mexican captives and talking with Joseph and Caesar. Interestingly, it was pointed out that when Wamuu and the others awoke they were speaking in Latin, due to their last battle having been against the Hamon users of Ancient Rome.

In Stardust Crusaders.... it's hard to say. It's only natural that Jotaro and Cherry-kun Kakyoin converse to each other in Japanese, yet it's never really pointed out that Joseph switched to speaking Japanese upon arriving in Japan, and the thought of an Egyptian man like Avdol speaking to a Frenchman like Polnareff in Japanese is weird as well. It'd be easy to just assume they all just spoke Joseph and DIO's native language of English or something, but it requires quite a bit of suspension of disbelief to assume two teenagers who spent their whole lives in Japan would suddenly speak fluent English.

Thoughts?

 

[Captain Cadaver]

The meta answer is they're just speaking "plot language" as in most series with different cultures interacting without cast members being known polyglots as to simplify things 2.

For an actual answer, I'd also assume English for most of Part 2 as it seems more likely a military official involved in foreign affairs like Stroheim would be more experienced in foreign languages than Joseph. Part 3 is more difficult to judge. English could work when Jotaro is part-American, though Kakyoin also being fluent in it seems questionable. I'd still say it's more likely than Polnareff (and the multiple side characters on the journey) having perfect knowledge in Japanese or the whole cast conversing in Arabic to Avdol though, especially considering English and French are the most closely related language out of the Stardust Crusaders' native tongues.