Overlaps occur when the Teacher and Students are talking at the same time. Given the type of lesson, would you expect there to be multiple voices active at the same time? Overlapping voices can occur because members of the class are engaged in lively conversations or activities, or because they aren’t really listening to what others have to say.
If you think you or your students need some help reducing Overlaps, here are some resources that may help:
Dealing with interruptions
When Students are interrupting others
Facilitating better listening