Stichomythia is the technical term for an extended dramatic passage in which two characters speak alternating lines of verse. There's also hemistichomythia, in which the characters alternate half-lines and distichomythia, in which they alternate couplets. The device was fairly common in classical Greek tragedy, and Renaissance playwrights often adopted it. The term is often extended to rapid-fire alternation in prose, such as Abbot & Costello's famous Who's on first routine Abbott Strange as it may seem, they give ball players nowadays very peculiar names. Costello Funny names? Abbott Nicknames, nicknames. Now, on the St. Louis team we have Who's on first, What's on second, I Don't Know is on third— Costello That's what I want to find out. I want you to tell me the names of the fellows on the St. Louis team. Abbott I'm telling you. Who's on first, What's on second, I Don't Know is on third- Costello You know the fellows' names? Abbott Yes. Costello Well, then who's playing first? Abbott Yes. Costello I mean the fellow's name on first base. Abbott Who. Costello The fellow playin' first base. Abbott Who. Costello The guy on first base. Abbott Who is on first. Costello Well, what are you askin' me for? Abbott I'm not asking you—I'm telling you. Who is on first. Costello I'm asking you—who's on first? Abbott That's the man's name. Costello That's who's name? Abbott Yes. The device is not restricted to Q&A situations, but of course it's admirably suited to them.