Definition:
A turn-construction unit (TCU) is the smallest unit of talk that constitutes a recognizably complete contribution to conversation. TCUs can be single words (“Yeah”), phrases (“On the table”), clauses (“If you want”), or full sentences (“I went to the store yesterday”). At the end of a TCU, a transition-relevance place occurs — a point where another speaker may legitimately take the floor.
In-Depth Explanation
The concept of the TCU comes from Conversation Analysis (CA), a research tradition that studies how people organize talk-in-interaction.
How TCUs work:
Speakers construct their turns from one or more TCUs. Listeners project (predict) when a TCU is about to end based on syntax, intonation, and pragmatic completeness:
| TCU Type | Example | Complete? |
|---|---|---|
| Single word | “No.” | Yes — syntactically and pragmatically complete |
| Phrase | “In the morning.” (in response to “When?”) | Yes — contextually complete |
| Clause | “Because she was tired.” | Yes — explanatory purpose fulfilled |
| Sentence | “I think we should leave early tomorrow.” | Yes — full proposition expressed |
| Multi-unit turn | “I went to the store. They were closed. So I came back.” | Each sentence is a TCU, but the speaker holds the floor through multiple units |
Projectability:
The crucial feature of TCUs is that listeners can project when they’ll end. In English, this projection relies on:
- Syntax: Once a subject and verb appear, listeners anticipate an object or completion
- Prosody: Falling intonation signals completion; continuing intonation signals more to come
- Pragmatics: Has the speaker accomplished a recognizable action (answering, telling, requesting)?
Japanese poses interesting challenges because it is a verb-final language — the key information (the verb, including tense and politeness) comes at the end. This means TRP projection in Japanese relies more heavily on particles, fillers, and prosodic cues than on syntactic completion:
- “明日は…” (Ashita wa…, “Tomorrow…”) → the は (wa) topic marker projects that more is coming
- “行きました。” (ikimashita, “went.”) → falling pitch + polite past tense = complete
Related Terms
See Also
Research
- Sacks, H., Schegloff, E. A., & Jefferson, G. (1974). A simplest systematics for the organization of turn-taking for conversation. Language, 50(4), 696–735. — The foundational paper defining TCUs and turn-taking organization.
- Tanaka, H. (1999). Turn-Taking in Japanese Conversation: A Study in Grammar and Interaction. John Benjamins. — Examines how TCUs and turn-taking work in Japanese, a verb-final language.