Is the use of "だって” regional or is it used everywhere?

Question

I recently came across "datte" for example: "だって眠くないんだもの" Is this specific to a dialect or used all over Japan?

Answer 1

This だって is a word recognized by dictionaries. It is a part of the Standard Japanese vocabulary and safely understood in casual conversation without showing peculiar color, if not everyone from every region uses it spontaneously.