As you can see under Forms in Danish Talk in Interaction, there are many different sizes of grammatical units: The smallest type is the singular-sound, which doesn’t have any content but is the building block for those words which are used in the Danish Talk in Interaction. The biggest unit is the discourse-unit. This could be a long story telling, which is one unit even though it consists of many sentences.
Our view on what could be a unit, depends on what the participants in the conversation treat as one or more units. Here, the term turn construction unit (TCU) is important. A TCU is a piece of speech which can constitute a turn at talk. Those TCU’s which are normally distinguished from one another are words (lexical units), phrases (word groups), simple sentences, and complex sentences.
The following example illustrates these turn construction units.
AULing | HLL | Broed | 11 ((telefon))
01 ((telefon ringer))
02 Len: det e:r lene↗
this i:s lene↗
03 Joh: de:t johanne→
this i:s johanne→
05 Len: he:j↗=
06 Joh: he(h)j hva ☺laver d[u↗☺
hi what ☺ are you d[oing↗☺
07 Len: [ehehh=
08 Len: =·hh ☺je:g lige i bad↗ hh [hh☺
=·hh ☺ I’m just in the shower↗ hh [hh☺
09 Joh: [*nå:→ okay↘*=
10 Joh: =·hh jamen det var bare fordi jeg ville
=·hh well I just wanted to
11 Joh: høre om du ☺gad å køre forbi føtex
hear if you ☺could stop by føtex
12 Joh: å☺ ta' noget brød me'↘
and☺ get some bread↘
14 Len: jamen det gider jeg godt↗=
yea I can do that↗=
15 Joh: =b[are et eller andet↘ ]
=j[ust something↘ ]
16 Len: [(havde jeg sand'lig oss)]
[(I had already )]
17 Len: ☺tænkt (mig/på) å gø(h)re→ hh hh☺
☺thought about doing that→ hh hh☺
At line 05 and 09 we see words which stand alone as turns at talk. In line 15 Johanne’s contribution is just something, which is a nominal group. Line 02 and 03 consist of simple sentences, and line 10-12 is a more complex sentence. These different kinds of units work as independent contributions to the conversation and are also treated this way by the other participant in the conversation.
What is crucial for an element to function as an independent unit in a conversation, is therefore not if it has a certain structure - e.g. that is it a sentence (under Forms you can read more about sentences as units). Instead, what is crucial is that it in the context is treated as an independent contribution that can constitute an action. It is therefore the participants of the conversation who decide if something is a TCU or not. These cannot be defined once and for all, but our experience tells us that words, ways of talk, and sentences can constitute TCU’s and often also are treated in this way.
Sacks, Schegloff & Jefferson (1974) is a scientific article, which represents the term turn construction units.
Steensig (2001) is a book and a large part of it revolves around the claim that turn construction units are the basic unit in conversation.