Other versions used (at least in AmE) are 'mother', 'ma', 'mama', 'mommy', and 'momma'. I'm sure there are more.
My college roommate's fiance called her parents by their given names. I just assumed she was adopted since she always called her mother 'Susan' and father 'Robert', but he said that no, she had the unusual habit of calling her natural parents by their real names instead of some kind of variant of mother/father.