I am not fluent , most Americans are not fluent in English, that word is very subjective. I can speak and talk about any situation and hold my own in a conversation in the ( North only) it is a tonal language, and in the north we use 6 tones, in the middle , west and in the south they use 4 or 5 only, and it is very very difficult to understand anything they say. I learned only with the northern dialect but that is all that I wanted. I speak with a lot of slang and people really trip out and I often get " I have never heard a foreigner speak like you before" that is better than any drug or sex in the world when they tell me that. I put a lot of time and effort in learning. I still learn everyday. I will learn until the day I die. Just like with any language there are many different ways to explain things etc , I am always learning. My Vietnamese is very good and the locals are very very impressed with my speaking skills.