I had a lot of fun RPing an adventurer that spoke Hawaiian Pidgin. It gave him a real earthy feel. But alas, the position of adventurer and inability to communicate to the realm is kind of frustrating, In the end the character became a friend of King Moritz in Asylon, he appears sometimes when I am feeling extra creative.
But given what you have already stated about the character, I think an earthy accent and feel would be quite useful in fleshing out the personality. This tends to work best with male characters, I don't know why.
