listen in to something —(also: listen in on something)
1. listen secretly to a conversation:
- Little does he know that the shop’s owner is standing in the doorway, listening in to the conversation.
2. follow a radio broadcast:
- We recieved a positive response from everyone that contacted us after listening in to the show.
listen to something—
1. = listen in to something 2:
- I have just listened to the show with Marc Perrin and it was great.
2. follow what smb. is saying, etc.:
- Here are a few of the notes I took while I was listening to his sermon.
3. pay attention to smth.; heed smth.:
- The problem is, neither of the other two are particularly willing to listen to his advice.