dirt

[robert]

Ok this is robert's cousin and I dont really watch baseball but i was wondering:
What happens if the pitcher pitches the ball hits the dirt a few feet in front of the plate and and then crosses through the srtike zone, is this a strike, ball, or an illegal pitch. Also, if it is an illegal pitch what exactley does that mean? If it is an illegal pich can the batter swing at it? what happens if the batter swings and misses is it a strike? Please explain.