I couldn’t find any confirmation that it was his voice, but Brice is French and his English in the movie - which is virtually incomprehensible - sounds very much like the English of many people from France or Wallony. The younger generations speak the language a lot better, but most people of over 50 have a very strong accent when trying to speak English. If it wasn’t Brice’s voice, who’s voice was it then? And why would they have chosen a voice actor with such a bizarre accent? There was no other reason to give Brice’s character this background then to use it as an explanation of his accent.