it's totally different to Chinese and very difficult. For example, you can call everybody is "you" in English but in Vietnamese, when you look at someone who is older than you, you have to say "chú","bác" or "ông" to males and say " cô", "dì" or "bà" to females. That depends on their ages. Moreover, Vietnamese have a lot of accents and it's really hard to understand all of them even if you were Vietnamese. Generally, Vietnamese is so interesting and complicated but you'll love it if you try.
This subject's been brought up so many times. I reckon, it mostly depends on your native language. For instance, learning Russian for an English speaker would be a real struggle considering so many new grammar aspects comparing to a meager English. However, from a perspective of a native Polish speaker it's not so hard, because just after hearing a couple of sentences, without learning a word in Russian, you can either understand the main concept or, at least, distinguish some individual phrases.
As for me, I'd say Chinese. Although I can prove or second this statemant in no way, since I've never tried. It just what seems to be:)
I speak from experience.Chinese is one of the most diffucult languages in the world.I have started learn Chinese but then I gave up eventually.Learning Chinese takes a very long time maybe two years or three.
I agree with Bartek, it depends on your native language. No language is inherently more difficult, based on the fact that babies in every native tongue take about the same time to learn the language.
I agree with the above comments, I think that Chinese is one of the hardest language to learn. There are too many glyphs to memorize and also it has difficult sentence structures as far as I know. What about Vietnamese? Is it similar to Chinese?