Students are sometimes very worried about making mistakes in spoken English.The best way to improve is by speaking in English as much as possible and not worrying about getting something wrong.
It's very unlikely that you will upset someone by a mistake, so don't worry about that.
Just remember that London is a multi-cultural city and we are used to hearing English spoken in different ways. We don't mind!
If someone doesn't understand you, try using different words.
It's okay to say "Just a minute please... I'm thinking how to say this". I had to do this all the time in Japan recently, and people were very patient.
But try to pronounce words as clearly as you can. I was surprised when two Japanese men said "We're pirates"
Can you guess what they were saying? The answer is at the end of this post.
Did you guess?
They were pilots! And their English was excellent.