Harle doesn't have a French accent in the Japanese release...idk about Pierre...I'm fairly sure Kid still talks like that though...
...as for languages...there's the script of Zealian that Melchior uses on the Masamune...
Something IS writTEN down in an ancient era's hieroglyphic characters. I SHALL try decoding it......
I just used the Retrans since I have it handy & it's a bit more specific, I think, than the Woosley'd version...But yeah, if they had a different written language at one time, it's not unreasonable to assume they had a different spoken language as well...
Also...there's this bit from Magus, of course...
'Da zuma lafwa roh laira......'Be spun, betwixt heaven and earth......'In exchange for this earth's life......!
Which is the retranslated version we all knew as...
Neuga Zeina Zieber Zom...now the chosen time has come...exchange this world for...!
Whether Magus' words are actually part of that ancient Zealian script (would a make moderate amount of sense, right?), some incantation actually required for his summoning, or just random gibberish he uses to focus his Magical abilities is, of course, completely up in the air...but if it's either of the former, that would give credence to the idea of the Chronoverse having multiple languages, if nothing else, than at some point in it's history...