How to learn Cambodian/Thai/Vietnamese language fast.?
First, are you wanting to learn all these languages? And what do you mean by fast? For a native English speaker, Thai would probable be the easiest, but not easy. Pimsleur is a good start but you’ll never become fluent using a “program”. I suggest you decide what language you want to learn first and start with whatever you can get your hands on. But in order to become fluent in any language you’ll have to spend time with a native speaker. If you’re able to practice with a native speaker, I’d give yourself 8 to 10 months (two hours per day) to reach a level 2 fluency.