[HUE]

You mention that they are fine with reading and writing, but are shy and quiet when it comes to speaking. So give them a lot of time to practice speaking. Drill sentences and give them time to practice in pairs. This builds confidence, and gets the pattern down. Then move to larger group activities. If I were to do an interview BINGO game, it might look something like this:

1. Present vocabulary through pictures. Read, repeat, and understand.
2. Use vocabulary in sentences. Again, read, repeat, and understand. Move on to a drill in which pairs are asking and answering with the sentences just practiced.
3. Switch partners, and repeat questions. This time take notes, and present to a third partner at the end.
4. Interview BINGO.

You'll also notice that after practicing so much, and because everyone is speaking at the same time, people will be less shy. There's also the competition factor, which gets students less concerned about speaking and more focused on winning!