I dont use the third person but I do talk to myself. Actually, I write Q-n-A withmyself to understand better some of the things I think (like my values, my goals, my opinion on stuff). I don't think it's anything like schizophrenia or anything. Talking to yourself does not mean you have any kind of personality disorder, as long as you don't start growing different personalities (and disagreeing with yourself does not mean you're growing another personality, it means you have doubts and are trying to solve them).