[the Obscure]

At least for the two first year classes, the kids probably don't have a lot of vocabulary to draw from. You'll need to introduce some vocabulary and simple grammar if you want to get them talking.

Here's an example of something I do for my elementary school students:
Let's say you want to start teaching them "How are you?" / "I'm fine, okay, great, happy, sad, sick, tired."

First, introduce the vocab and make sure they've got the hang of it. This should only last about 8 to 10 minutes.

Then do a game to help them with their listening. Karuta (also called Snap or Slam) is a good way. Split the kids into small groups and have a bunch of flashcards with the pictures of the vocab you're using. When you call out a word, they race to slap the card first. To make sure they're listening, say words that have already been called (that they can't slap anymore). That way at the end of the game, when only the last vocab word is left, they actually have to listen to make sure that you're saying the word that's on the card.

Next, do a game to get them speaking. Battle Janken (sometimes called Touch the Base) is a good one that kids usually love. Set a bunch of flashcards out in a line either on the floor or on a bunch of desks/long table. Split the kids into two groups and have them line up at either end of the table. Say start, and one kid from each team has to race down the line of flashcards, saying the correct vocabulary word for each card. Once the kids meet in the middle, they do rock paper scissors. The kid that wins continues down the line of cards. The kid that loses has to return to the end of the line for their team, and the next kid in line starts racing down the line of cards. They keep doing this until one of the teams is able to get to the end of the line of cards (which will be in front of the other team) and wins the RPS battle. My kids love this game because there is never any way to know who will win. Even if a kid gets all the way down to the other end of the card line, they can lose the RPS battle. The kids that aren't as good at English can still win for their team if they happen to luck out with RPS.

Then do a call/response game to get them started on a conversation. Having the kids speak in groups helps the shy ones that are worried about making mistakes. Split the class in half and give each group a card for them to feel (So, team A gets "I'm great!" and team B gets "I'm sick."). Team A starts and asks "How are you?" to team B. Team B responds "I'm sick, and you?". Team A says "I'm great!" Then you give them new cards and have team B start the dialogue. Do this a few times so that the kids are comfortable with it. You can have the kids try to shout louder than each other, or say it more quietly than the other team to get the energy going, if you want.

By this time, the kids will probably be ready to mingle and talk to each other on their own. You can give each kid a card for how they're feeling. You can tell the kids that they have to race to try to talk to the most kids in class in a certain amount of time. The student that talked to the most people can get a sticker or something, if you want to bribe them. Have the kids do RPS to decide who asks "How are you?" They do the dialogue: A "How are you?" B "I'm _____ and you?" A "I'm ____. See you later!" B "Bye!" (Or whatever you had them practice before).

If they're not ready to be on their own, you can have them RPS with you before you send them off on their own.

Sorry that was really long. It's just an example of something really basic. Hopefully you can get some ideas.

Good luck!