Logorrhea
-noun
1. Pathologically incoherent, repetitious speech.
2. Incessant or compulsive talkativeness; wearisome volubility.
By his own measure, he is a man of many contradictions, beginning with the fact that he is famous as a listener but suffers from a touch of logorrhea. He is so voluble that one wonders how his subjects get a word in edgewise.