My point is: Forget the vocabulary and the grammar. Only the things you want to say matters.
I live in a small city in China and it is weird to see foreigners walking down the street when I was in the elementary school. At that time, I learnt English and was pushed to take classes once a week where I have to meet a tall, blond hair teacher, who always kept a warm but confusing smile.
At first, I was afraid of her questions even they were easy to answer. But still, my name was called and I stood up with a awkward blush. However, it was a relief that I know the exact word at that time and somehow my answer pleased her. Since then, she could recognize me when I greeted to her.
I still dare not to raise up my hands in her class. But the thing is, every time she asked a question and the whole class was in a dead silence, she would look directly in my eyes and I have to save the situation. Chances came that I couldn't find the proper word to answer questions shortly, so I had to use clumsy sentences and words to explain my ideas. It was hard at first. I use a lot of gestures and facial expression to cover that. And gradually, I found it was not as awkward as I thought to "talk" with her in such way, and even better, I could grab some of the right sentences to communicate with her.
And thanks to have such experience, a few months later, when I entered the room to meet the examiner in IELTS test, I felt free to express. I am not saying I have no trouble talking to a foreigner, you see, my vocabulary is poor and my sentences are dull. But I did not act nervous and forget everything.
So next time, try to talk to a foreigner, not speaking a foreign language to a foreigner. Language is just a tool. Feel comfortable and overcome the nervous feeling, then it can really works.