A turn is the time when a speaker is talking and turn-taking is the skill of knowing when to start and finish a turn in a conversation. It is an important organisational tool in spoken discourse.
One way that speakers signal a finished turn is to drop the pitch or volume of their voice at the end of an utterance.
In the classroom
There are many ways that speakers manage turn-taking and they vary in different cultures. Areas that can be considered in language teaching include pronunciation, e.g. intonation, grammatical structures, utterances such as 'ah', 'mm' and 'you know', body language and gestures.