Made some example. Sorry it's crappy haha.


So, first one. You can use tw different bubbles. On here I made a long vertical one and two horizontal one. Since it's three language, I p two box on the bottom for translation. (forgot to add * to specify who's talking).
Over here, I made the vertical in English, which I assume the most used language in this situation. The other tw were in the not usually spoken by the characters.
On example two, I put the translation directly under it, so no box on the bottom, but bubbles must get bigger. The text need to be a little smaller or in different font (but still easy to read).
On example 3, I use bold and that continued letter (my brain can't conjure the name atm lol), to differiate the language, but it's in English. If this is only in two language or the different Language Wasn't really something that's often showed up, I probably wouldn't bother with different font.
Also, In this case you need to remind your reader outside the panel what language they're speaking of From time to time, if the language wasn't spoken often.
There's some other Ways like different colored bubbles like you said, but if you're still not sure, why not make some page examples and let your reader choose which one they deemed more comfortable to read? ¯_(ツ)_/¯
Also, you can ignore the last one. UwU