no it is not normal so i can understand how you may be troubled by this nasty habit. in most cases this is just a habit that is going to require some behavioral modification on your part. just like nose-picking nail-biting and other habitual things that kids develop you will just need to be firm (but nice) on your efforts to control the licking habit. make sure he is not eating things he should not be eating (called "pica") too. habit control is more complex than can be addressed by this forum but positive reinforcement of good behavior works very well. give him a big hug (and an m&m) for not licking things and share your disappointment (and no m&ms) when he does lick the floor or?
is it normal for a 2 year old to lick everything?