The idea was introduced in "A Simplest Systematics for the Organization of Turn-Taking for Conversation" by Harvey Sacks, Emanuel Schegloff, and Gail Jefferson in 1974.
The model also leaves puzzles to be solved, for example concerning how turn boundaries are identified and projected, and the role played by gaze and body orientation in the management of turn-taking.
It also establishes some questions for other disciplines: for example, the split second timing of turn-transition sets up a cognitive 'bottle neck' in which potential speakers must attend to incoming speech while also preparing their own contribution - something which imposes a heavy load of human processing capacity, and which may impact the structure of languages.
[2] Interaction in more specialized, institutional environments such as meetings, courts, news interviews and mediation hearings have distinctive turn-taking organizations that depart in various ways from ordinary conversation.
A transition relevance place (TRP) is a point of possible completion (or potential end) of an utterance (hence a TCU) where speaker change is a possible next action.