Number 1: Paper chains
Paper chains are easy and cheap. Here are two ways to use them.
For Correction: Start with a paper chain of 10 links (or however may you choose.) If a student is speaking in any other language than English during class, you remove one chain. This continues every day for a week. If there are any links left on the chain at the end of the week, the students earn 10 minutes of free time, a game of UNO (or any other incentive that works for your students.) This method works because of the positive peer pressure of earning a reward as a group.
For Positive Reinforcement: Start with 10 strips of paper. Every time the class makes it through a class speaking only English, you can add a link to the chain. Once you get to 10 links on the chain, the class earns 10 minutes of free time! Again, positive peer pressure makes this a powerful tool.
Number 2: R E S P E C T
Start with the word RESPECT, each letter written on a separate piece of paper. I use magnetic paper so I can stick them on my marker board. Explain to the class that speaking in English shows respect: respect to the other people in the room who cannot understand them, respect to the teacher and what s/he is trying to accomplish, and respect to their parents who have put them in this school in part in order to learn English.
For Correction: The entire word is attached to the board at the front of the room. Any time a student speaks in a language other than English, one letter is removed. This continues for an entire week. If there are any letters left, the students earn free time, game time, 10 minutes of funny Youtube videos...whatever floats their boat.
For Positive Reinforcement: Every time the class makes it through a class speaking only English, you can add a letter to the board. Once you get the entire word RESPECT on the board, the class earns 10 minutes of free time!
Kids are quick to pick up on the fact that they could speak in their native tongue until the end of the week being careful not to exceed the limit. In order to keep this from happening, I have added the following rule:
If there is only 1 chain left or letter left (whichever method I am using at the time,) they earn 5 minutes of free time, but if they have more than 1 left their prize is doubled.
Even better than free time...I have found the best incentive is my prize jar. In my jar there are an equal number of "great prizes" and duds. I have 24 slips of paper folded in a jar. 12 have a variety of prizes (free time, game time, homework pass, etc.) the other 12 have the words "tough luck" written on them. If the class has the entire word RESPECT on the board they can draw from the jar 2 times on Friday. If they have only one letter left, they can draw 1 time. If they have no letters, they get no draws. The more opportunities they have to draw a prize, the higher their chances of getting something good!