Conversation coordinates joint activities and the joint projects that compose them. Participants coordinate (1) vertical transitions on entering and exiting joint projects; and (2) horizontal transitions in continuing within them. Transitions are coordinated using project markers such as uh-huh, yeah, right, and okay. In the authors' proposal, participants use uh-huh, yeah, and right to continue within joint projects, and okay and all right to enter and exit them. This was examined in 2 telephone conversation corpora. Telephone conversations divide into an entry, body, and exit phase, each of which is a joint project. Okay and all right were used to transit from the entry to body and from body to exit, whereas uh-huh, yeah, and right were used within the body.