In this paper, I look at the properties of this type of parenthetical and at the sequence that may develop out of it. In particular, I examine the construction and placement of the insert in the ongoing TCU, its prosody, the way the recipient responds to it, and how the speaker accomplishes the return. The analysis describes how linguistic structure is deployed as a resource for performing a subsidiary interactional activity in the course of the unit with the action it is supportive of.
Parenthetical sequences are a solution to a design problem. The device enables a speaker to reconcile the potentially contradictory requirements that the linearity of speech production poses to the speaker's orientation to recipient design.