In their description of the turn-taking system, Sacks, Schegloff, and Jefferson (1974) make explicit some relationships between turn-construction unit types, speakership transition, and projectability:

There are various unit types with which a speaker may set

out to construct a turn. Unit types for English include

sentential, clausal, phrasal, and lexical constructions ...

Instances of the unit-types so usable allow a projection of

the unit-type under way, and what, roughly, it will take for

an instance of that unit-type to be completed .... The first

possible completion of a first such unit constitutes an initial

transition-relevance place. Transfer of speakership is

coordinated by reference to such transition-relevance places,

which any unit-type instance will reach. (702-703)

Note two aspects of this description. First, it refers to possible unit types as spoken (and, in this case, specifically English), and we have observed that co-present interactants make use of nonvocalized embodied actions to construct turns in interaction. That is, it is empirically observable that participants may take turns without speaking. So, Proposition One is an extension of this turn-taking description.

Second, the criteria for usable turns are projectability of kind-of-unit and of possible completion. But the descriptin of the turn-taking system includes specifications for how participants project possible completion points:

Sentential constructions are capable of being analyzed in the

course of their production by a party/hearer able to use such

analyses to project their possible directions and completion

loci (709).

However, in the specific instances of interaction examined in this study, it is demonstrated that embodied actions -- which may not include "sentential constructions" -- are recognizable to recipients during the course of their physical unfolding, and they are built in such a way as to provide for the anticipation of turn transition relevance. Sacks, Schegloff, and Jefferson explicitly specify that a viable turn-construction unit must have this feature of recognizable projectability (Section 4.13):

... whatever the units employed for the construction, and

whatever the theoretical language employed to describe

them, they still have points of possible unit completion,

points which are projectable before their occurrence. (720)

How embodied actions achieve recognizable projectability is taken up in detail in Chapter Four. For now, our concern is to demonstrate that embodied actions are drawn upon (recurrently) as "units employed for construction" of viable turns. According to Wilson, Wiemann, and Zimmerman (1984), "the notion of unit-type should not be restricted to words, phrases, clauses, and sentences, but instead be viewed as a variable unit" (177). The data presented here demonstrate that nonvocalized actions are used by co-participants as "unit-types." In his study of talk and recipiency, Heath (1984) focused on what he termed "nonvocal components" of sequential structures in the interaction (250), and this research presents further findings organized around Proposition One.