In a film, radio or television studio, the private sound system that lets one person speak to another without the audience or the microphones picking it up — most often the director or producer in the control room speaking into the earpiece of the presenter on camera. It works one way or both ways depending on the setup, and the same word covers both the system and the equipment: the talkback box, the talkback button, "she heard it on talkback". It is technical, industry vocabulary, so you meet it among people who work in broadcasting rather than in general conversation. Two things to note. In Australia and New Zealand the same spelling means something completely different in everyday speech — a radio programme where listeners phone in and give their opinions (talkback radio), which British and American speakers call a phone-in or a call-in show. And the word can be used as a verb in the studio sense: "the producer talkbacked to him during the interview", though this stays inside the trade. The plain two-word phrase to talk back, meaning to answer a parent or teacher rudely, is a separate thing and is not what this entry is about.

（攝影棚、廣播用的）內部對講系統、導播對講；在澳洲、紐西蘭則指「聽眾call-in節目」