EXAMPLES FROM THE WEB FOR YEAH
"Yeah, but—" Lane shook his head and turned back to the window.
Yeah, Doc, the only way to get anything out of you is to blast it out, isn't it?
Yeah, with the muzzle about a foot from my head when he let go.
"Yeah, I been kinda wondering about you," he added conversationally.
"Yeah, it sounds like a rumble," one of them says, after a while.
"Yeah, the Legals want the Crusader for their propaganda," he said wearily.
Blackwell swallowed hard and nodded and said, "Yeah, that's Jack, all right."
Yeah—thanks—no idea how sensitive people are when you get their names wrong.
Yeah, I guess I do, Frankie, but not bad enough to win it the wrong way.
"Yeah, about the same time of day," Jed said, and looked at him curiously.
American English, colloquial, by 1863, from drawling pronunciation of yes.