Answer:
Just speak anyhow you can.
Step-by-step explanation:
The problem you are having is that you probably think you would commit a blunder if you contribute to the discussion. This is the fear holding you back.
You have to learn how to face this challenge by not paying attention to your diction. Just do you.
You can only learn by doing. If you are afraid to commit some blunders amidst your friend, how would you interact with a stranger?
Dare to dare.