People who talk over you?

Recently I have come across a few people who want to completely dominate the conversation. They will even pause, wait until I start talking, and then talk over me. So during the whole conversation I am laboring, constantly trying to put a word in edgewise. 99% of the people I talk to are not like this and I was wondering if it was intentional thing meant to belittle others, or a problem that the person has like an inability to conversate correctly.

Any ideas as to what this is? Ego, attempt at dominance, some psychological condition? I try to have empathy with everyone but I am not sure if these conversation mongers are attacking me or if they have a problem.