I couldn't speak ...

I couldn't speak English as much as I hoped today. As I wrote it yesterday, I got a workout of the new system that our company became to handle in English. I always think something when I talk with the foreigner who speak English. Even if I want to ask some question to him and could ask it to him properly, I may not understand his answer. Actually, I could sometimes understand his explanation and sometimes couldn't understand it today. I felt the much frustration of not knowing the answer. It is difficult for me to understand the technical issue in English because I don't know if I can understand it even in Japanese. One thing I know is what I am severly deficient in my English skill of listening and speaking. This experience stimulates me. First, I think I have to read English faster than I do now. Also I have to think things in English when I write something in English. (Although I know that, it is difficult for me to do that.) Also I have to build up my vocabulary. These 3 points is the key of inproving my English skill, I suppose.