Write down a phrase on a piece of paper. Depending on the level of the class make this as simple or as complex as they can manage.
Get the students in a row and whisper the phrase to the first student. This first student then whispers it to the next student who whispers it to the next and so on till the final student hears the phrase, goes to the board and writes it down.
Then you write down the phrase on the paper and compare them.
The chances are - especially if you have a good opening phrase - that the final phrase will bear little or no resemblance to the original. You can choose your words carefully here to point out common pronunciation errors in English and of course use words the students may need to revise and check.
One additional bonus for the TEFL classroom is that students must be very quiet; they must also speak slowly and carefully and listen carefully to what is being said.
Picture Whispers is a good variation to try out.
Divide the class into teams. At the front of the class put a picture on a desk. The first student in each group runs forward and looks at the picture, they must then go back and tell the second in line one element of the picture to pass down the line; the last person in the line must draw it.
And so on. The teams have 5 minutes to complete the picture and, of course, if the drawer needs help or clarification of a point they must pass a message back up the line to the first student.
The winner is the team which has a picture most resembling the one at the front of the class.
If you arrange the students in a circle, you can start sending one message one way and a completely different message another way. They will cross in the middle and often get confused at this point.
With younger students, it can also be fun to add a "face" to the message: the message is passed on literally face-to-face but with an expression added, e.g. big smile, grimace, one eye shut and the other open, etc.Image © Sambhu Sankar