Chuong Van Nguyen
join a conversational English club or go for some professional elocution lessons.
And don't forget to
use English
everyday: do
not be afraid of losing face.
We learn by making mistakes. Embrace your mistakes. All that losing face stuff is nonsense anyway

.
Go for it and good luck (it'll take a lifetime, y'know [I'm still learning and I'm from England]).
BTW I spotted the deliberate spelling mistake in your post

.
Atm