Before revision: "Yeah", a "Lexical filler", is used to give affirmation, introduce a new topic, shows speaker's perception and understanding, and occurs after a speech management problem when the speakers does not how to continue their speech.
After revision: know"Yeah", a "Lexical filler", is used to give affirmation, introduce a new topic, shows speaker's perception and understanding, and occurs after a speech management problem when the speakers does not how to continue their speech.