Okay, curiosity's good. Didn't I say I was?
Just for fun, how about we say which part of our Language Family our mother tongue is?
My Indo-European mother tongue is Dutch --> which is part of --> Germanic --> which is part of --> European --> which is part of --> Indo-European.
Confusing? Nah. Try a Tolkienian Elven tongue, if you want confusing!
EDIT: Welllll...... my parents' parents' mother tongue is Dutch. I barely know the language. Jah.