Following a recent conversation in a school about evidencing Talk, I created speech bubbles for Talk Observers.
The idea is that during dialogue opportunities, some pupils take on the role of Talk Observer. They listen for examples of children speaking in full sentences, using powerful language, demonstrating reasoning, and so on, and write these in the speech bubbles.
This creates a record of the quality of Talk occurring in your school, and may also help the Talk Observers themselves gain familiarity with Pupil Talk Prompts and different sentence structures.
In EYFS, or situations where you want every pupil to participate in the dialogue, additional adults could act as your Talk Observers.