Turn construction(al) unit

A turn constructional unit (TCU)  is an action (spoken or embodied) that makes up a turn at talk. A turn may have one TCU (e.g. “yeah.”) or can be made of more than one TCU (e.g. “yeah. (0.2) I thought we could make a booking for Sunday, (0.7) or do you want to wait and see?”). Each unit, or part of the turn, could function as a complete part of the turn and is recognisably complete.

Here’s an example from Sacks, Shegloff & Jefferson (1974, p. 721):

(25)  Tourist:    Has the park changed much,

      Parky:      Oh:: ye:s,

                   (1.0)

      Old man:    Th’ Funfair changed it ’n [ahful lot [didn’ it.

      Parky:                                 [Th-       [That-

      Parky:      That changed it,

The boundaries of each TCU mark a turn transition relevance place (TRP) (i.e. where another speaker could take a turn), as we see in the example above where Parky begins his turn at each TRP. So “the funfair changed it”, ‘an awful lot”, and “didn’t it” are all TCUs.

“The turn construction unit (TCU) is defined as a unit of talk that makes up a turn in talk and is comprised of sentences, clauses, or even a single word… it refers to pieces or segments of an interaction that make up a complete turn in the talk”. (Lester & O’Reilly, 2019, p.30)

“Turns are composed of one or more turn-constructional units (TCUs), which consist of linguistic units (words, phrases, clauses, etc.) that form a recognizably complete utterance in a given context.” Hoey & Kendrick (2017, p.153).

“The building blocks out of which turns are fashioned we call turn-constructional units, or TCUs. Grammar is one key organisational resource in building and recognising TCUs: for English and many other languages (so far we know of no exceptions), the basic shapes that TCUs take are sentences or clauses more generally, phrases and lexical items. A second organisational resource shaping TCUs is grounded in the phonetic realisation of the talk, most familiarly, in intonational “packaging”. A third — and critical — feature of a TCU is that it constitutes a recognisable action in context: that is, at that juncture of that episode of interaction, with those participants, in that place, etc.” (Schegloff, 2007, p. 3-4).

References:

Elliott M. Hoey, Kobin H. Kendrick, (2017). Conversation analysis. In A. M. B. De Groot & P. Hagoort (Eds.) Research methods in psycholinguistics and the neurobiology of language: A practical guide (pp. 151-173). Wiley Blackwell.

O’Reilly, M. & Lester, N. (2019) Applied conversation analysis: Social interaction in institutional settings. London: Sage.

Sacks, H. Schigloff, E.A. & Jefferson, G. (1974).  A simplest systematics for the organization of turn-taking for conversation. Language, 50, 696-735.

Schegloff. E. A. (2007) Sequence organisation in interaction: A primer in conversation analysis, Volume 1. Cambridge: Cambridge University Press.

Dr Emily Hofstetter has an excellent explainer of TCUs on her YouTube channel “Em does CA”.