What role does incoherent language play in Othello? How does Othello’s language change over the course of the play?

At the beginning of the play, Othello's speech is articulate, intelligent, and effortlessly engaging. The more Iago antagonizes him, the more this changes. In the third act, Othello's language becomes clipped, incoherent, and hesitant. The more upset he becomes, the more repetitive his comments.

By Act IV, Othello doesn't seem to have a mind of his own. He echoes Iago's words, doesn't seem to be able to articulate his own thoughts, and more importantly doesn't seem to have any of his own thoughts. Iago succeeds in making Othello a puppet, and then unable to bear it any longer Othello physically collapses.