pipe up
To make oneself heard; to interrupt or interject. The meeting was just about over when Tom piped up and asked why we hadn't looked at the budget. I'm sorry, if you can't hear me, just raise your hand and I'll pipe up.
pipe up (with something)
Fig. to interject a comment; to interrupt with a comment. Nick piped up with an interesting thought. You can always count on Alice to pipe up.
pipe up
Speak up, as in Finally she piped up, "I think I've got the winning ticket," or Pipe up if you want more pancakes. This term originally referred to a high, piping tone. [Mid-1800s]
pipe up
v. To join a conversation with an opinion, especially unexpectedly: You should have piped up if you didn't agree with us.