Question: Location?

There are plenty of biblical-themed films in which most or all of the actors have American accents, from C.B. De Mille's "The Ten Commandments" to Scorcese's "The Last Temptation of Christ."

Although technically not a biblical film, Stanley Kubrick's "Spartacus" used British actors to play the patrician Romans and American actors to play the slaves. That bit of "accent casting" was done intentionally to emphasize the class differences between slaves and citizens.

Yes, the language thing in the Pink Panther movies is a bit odd. The characters are supposed to be French. The actors, with the exception of Sellers, speak English with no attempt at a French accent. And there's a running joke making fun of French pronunciation, e.g., "I was told your pheune is out of order," or "I have reason to believe the thief is in this reum."

Don't try to dissect it. It's comedy.