Yeah, at first I was hesitant at a voice with an accent and then I remembered that all the Imperials sounded British, Watto was Jewish, the Federation were flat out racial slurs against Asians, and the original Jar Jar was such a stereotype that he might as well have said "Yessem Massa, I be pickin the space cotton" before beating up the tar baby for not responding when he said "Howdy."

There is certainly a precedent, especially considering its the accent Lucas has often described as his vision for what Threepio should have sounded like. And at least the voice is just an accent and not flat out offensive like some of the aforementioned.