He also worked hard on his pronounciations too. We talked the whole night in English. He was surprized that I am speaking with near perfect North American pronounciations while I came here at late 20's and now in 30's. I also mentioned to him that a guy called Jerry did it so well at the age of 20's. I said you should be doing better because you came so young. Today I received an email from him again asking me to correct his pronounciations to North American accent. If you want to exchange ideas with me, I welcome you people who have same interests. I remember the night the guy said to me: Now you don't need to improve your pronunciation any more, because you're already doing near perfect. But as you said and I agreed, there is always room for improvement.