No. In essence self talking is very different from talking to others. First off, self talking can give you time intervals to prepare your articulations and expressions, not included in real dialogues with others. Secondly, self talking is not emotional and you can keep calm or totally control your emotions, literally different from real conversations. Thirdly, if you don't apply 'new fluencies' into your speeches, even though you practice talking for millions of times, they'll all be in vain cuz your speech cognitions and methods are still unchanged, which you haven't learned from decent speech therapies. Finally, if you are not a solo living male in a mansion, sparing too much time on talking to the you in the mirror will scare the st out of your roommates, parents or your wife LOL.