Mamaṃ etad cetaso parivitakko udapādi: (This train of thought occurred to me) What if Buddha spoke two or more different languages?
it has never crossed my mind, though it seems plausible: Ancient Indians knew many slightly different languages, and for the learned middle and high social class or strata persons it was a "must" to know the language of the sophisticated culture, some local "high" languages, and the vernacular widely spread languages. We know that Buddha was a learned person, why should we suppose that he knew only one language?
How good and wonderful are your days,
How true are your ways?