In Vietnam approximately 90% of Vietnamese English teachers failed a government competency test. I have met about 50 Vietnamese English teachers and not one could speak English fluently or correctly but all of the Vietnamese teachers had superior grammer skills than I; most university level students knew their grammer inside and out but need pronunciation and comprehension (listening) exposure and for that reason need instruction from a native English speaker, preferably from the US or Canada or secondarily from Australia and then England. Even a backpacker teacher is better at teaching pronunciation than a Vietnamese teacher. So, to all of you wanting to improve your English; find a native speaker.