Suggested correction, hope it helps. 

I want to write about my success in learning English.

Today, I spoke with some people who know English very well, but I didn't understand everything that they said, because I know so few words.  (This section is unclear: "and often used vocabulary. namely it halp me in this difficult deal".  Do you mean that you had a few words that you used over and over again, and that made the communication easier?)