my poor writing

In last class I felt so awkward .
I thought both cases would give us some influences by each ways.But I hoped to watch movies(especially musical!), 'cause I was afrad of silence.
We can talk with each other easily in Japanese,but when we discuss in the class (or sometimes even talk in the small group),we zip up our lips and look down.
I talked about this problem with some classmates a few times,and found we had some common reasons for silence:

We don't know What to say(means "I have no idea!").
We can't make ourselves understood in English.

So these make silence, and silence makes us feel SO nervous.
However,whether we have much English vocabulary is not really the point,I think .It depends on our will.It isn't bad not to understand.If anything,we should say BY OURSELVES,"I have no idea."or"I can't undearstand what you mean." and so on.So we can put in a few words to help each other.
This is one style of the communication with others,isn't this?

I wish I could have exprss my opinion by myself in last class!!(＞＜)