Thanks for the information,
adsc! Have never thought about learning languages in such a complex way.

It sounds interesting. Were you talking about only the writting system or about speech perception too?
Dear
Turkcerap and
mrym, actually, Chinese grammar has nothing extremely difficult. It is very simple. Sometimes some people even say, there is no any grammar in Chinese. But there are many another difficulties in Chinese. As for me, these are:
* speech perception (auding);
* way of forming a sentence;
* and just third big difficulty for me are Chinese characters.
Let me explain.
Speech perception (听力) is the biggest problem for me, because Mandarin (普通话) is not rich in combination of vowels and consonants. I mean, there are not many possible phonetic syllables in Chinese. So sometimes it makes speech too difficult to perceive. For example, just one phonetic syllable "shi" (not counting difference in 5 possible tones for it, because the tones often cannot be clearly defined in fast speech) can be written with almost 70 different characters, so, figuratively saying, it may have about 70 different meanings.
Way of forming a sentence, because sometimes you can understand every character in a sentence, but still cannot understand idea of the whole sentence. Probably, the reason is a special syntax that is unusual for people, whose native languages belong to another families of languages. An additional hardship is undeveloped morphology. You may think that simple morphology makes a language easier. Yes, it does, but sometimes it raises some new problems. Sometimes a particular word in Chinese can be a subject (noun), a predicate (verb), an object, an attribute (adjective), and an adverbial modifier (adverb) at the same time (without any changes). Anyway, all words have a certain place in Chinese sentence, so you can see where any of them should be placed, but sometimes still have to guess what author meant.
Chinese characters (汉字)... Almost everybody heard about them and saw them. Undoubtedly, it is very special and difficult system of writing. People often face many problems regarding to memorization of Chinese characters (both writing or reading). But if you learn well enough, someday you will be able to read even some uknown characters. I would like to say that if you face some known character in a text it is rather easier to remember how it is read than if you need to remember how to write some character. Some people even invent original systems how to make memorization of the characters easier. And the idea of
adsc's post can help some people in it. Why not?