Put students in pairs and give them a scene to act out. They are going to have a conversation using an invented language. Explain to your students that gobbledygook is a made up language that is total nonsense. The pair should act out the scene using the correct intonation as if they were really talking to one another. The rest of the class can watch and guess what the situation is. After, you could write out the real dialogue in English for one of the scenes.
(Thanks to James Stewart from the British Council in Barcelona for demonstrating this in a workshop.)