Help!!! Can anyone help me to participate(talk) in classes?

Honestly there is no easy fix for this. You just have to put yourself in a situation where you have to talk. If you are really that uncomfortable with it and you are in school consider taking the dreaded speech class. It will force you to get up and talk in front of people. The best way to get over a fear like this is to tackle it. Hope that this helps and I wish you luck!

When I was younger, I found that I could participate in classes by asking QUESTIONS. So if you prepare a few well thought-out questions to ask in class beforehand, you may stimulate a discussion that may help you ease into the conversation. When you feel more comfortable speaking aloud, try your best to ANSWER a few questions from others each day.

If you do this question and answering, you will be "participating"!

From your posting, your English seems very good to me. I think the most important thing for you is to just be confident. I realize how difficult it is to speak a foreign language with confidence, but just trusting that you will be able to say the right thing is vital. It also might help you if you talked to your teachers and told them your problem so that they understood how hard it is for you. Just stay confident and don't give up!

Just let your fears go. If a topic comes up and you think you have something to say, say it, you will become more and more comfortable as you do this. It worked for me.