I don't know what accent they would speak, but I noticed today that it was mentioned in TSR that they use chopsticks to eat in Arad Doman. Each land appears to have a combination of different aspects from different cultures that exist in our world/time.
Now that I think about it, I wonder if...
I have been listening the the audiobook version lately, and the readers on those try to create an accent that is a little different for each character. I don't know if I agree with all their choices though. These are my guesses.
I don't know if it is Illianers in general or just Bayle Domon...