Because even looking up a word in the dictionary is complicated.因为连在字典里查一个字都很复杂。

One of the most unreasonably difficult things about learning Chinese is that merely learning how to look up a word in the dictionary is about the equivalent of an entire semester of secretarial school. When I was in Taiwan, I heard that they sometimes held dictionary look-up contests in the junior high schools. Imagine a language where simply looking a word up in the dictionary is considered a skill like debate or volleyball! Chinese is not exactly what you would call a user-friendly language, but a Chinese dictionary is positively user-hostile.
学中文中最不可理喻的困难之一,就是连学会查字典的难度都基本等于在文秘专业学一个学期。在台湾的时候我听说有时还有初中生查字典比赛。想象一下吧,有种语言里连查字典都成了跟辩论或是排球一样的技能!你多半不会称中文是个善待用户的语言,而中文字典则绝对是虐待用户的典型。

Figuring out all the radicals and their variants, plus dealing with the ambiguous characters with no obvious radical at all is a stupid, time-consuming chore that slows the learning process down by a factor of ten as compared to other languages with a sensible alphabet or the equivalent. I'd say it took me a good year before I could reliably find in the dictionary any character I might encounter. And to this day, I will very occasionally stumble onto a character that I simply can't find at all, even after ten minutes of searching. At such times I raise my hands to the sky, Job-like, and consider going into telemarketing.
找出所有部首和它们的变体,再加上处理那些没有明显部首模棱两可的汉字,这是个愚蠢的,花时间的苦差事。和其他拥有合理的字母或类似系统的语言相比,这一点大大放慢了学习中文的过程。我得说,我花了一年时间才能比较顺利的在字典中找到任何汉字。而直到今天,我极偶尔还是会遇到即使查个十分钟还是查不到的汉字。这种时候我就会像(圣经中信仰屡受考验的)约伯一样,举手向天,同时考虑去电话营销业之类的工作……

Chinese must also be one of the most dictionary-intensive languages on earth. I currently have more than twenty Chinese dictionaries of various kinds on my desk, and they all have a specific and distinct use. There are dictionaries with simplified characters used on the mainland, dictionaries with the traditional characters used in Taiwan and Hong Kong, and dictionaries with both. There are dictionaries that use the Wade-Giles romanization, dictionaries that use pinyin, and dictionaries that use other more surrealistic romanization methods. There are dictionaries of classical Chinese particles, dictionaries of Beijing dialect, dictionaries of chéngyǔ (four-character idioms), dictionaries of xiēhòuyǔ (special allegorical two-part sayings), dictionaries of yànyǔ (proverbs), dictionaries of Chinese communist terms, dictionaries of Buddhist terms, reverse dictionaries... on and on. An exhaustive hunt for some elusive or problematic lexical item can leave one's desk "strewn with dictionaries as numerous as dead soldiers on a battlefield."
中文肯定也是地球上最需要字典的语言之一。我现在手头有超过二十本各种中文字典在书桌上,每本都有单独用途:有大陆用的简体字字典,有香港台湾用的繁体字字典,还有简繁体都有的字典;有用威妥玛拼音的字典,有用大陆拼音方案的字典,还有用其他更超现实主义的拼音的字典;有经典的中文虚词字典,有北京方言字典,有成语字典,有歇后语词典,有谚语词典,有中国GCD用语词典,有佛教用语词典,还有反查用词典,不一而足。一次穷尽式的查询某个难解词汇可能会让书桌上“堆满词典,如同战场上的士兵尸体一样。”

For looking up unfamiliar characters there is another method called the four-corner system. This method is very fast -- rumored to be, in principle, about as fast as alphabetic look-up (though I haven't met anyone yet who can hit the winning number each time on the first try). Unfortunately, learning this method takes about as much time and practice as learning the Dewey decimal system. Plus you are then at the mercy of the few dictionaries that are arranged according to the numbering scheme of the four-corner system. Those who have mastered this system usually swear by it. The rest of us just swear.
查陌生汉字的时候还有一种四角系统的查法。有谣言说这方法很迅速,基本上和查字母语言的情况下一样快(虽然我没见过谁能第一次就找到正确的编码)。不幸的是,学习这个查法本身就跟学杜威十进图书分类法花的时间和精力差不多。此外你还得指望字典的确按照四角系统安排过(这类字典并不多)。那些掌握了这个四角查法的人对其推崇备至,我们其他人则是赌咒发誓。

Another problem with looking up words in the dictionary has to do with the nature of written Chinese. In most languages it's pretty obvious where the word boundaries lie -- there are spaces between the words. If you don't know the word in question, it's usually fairly clear what you should look up. (What actually constitutes a word is a very subtle issue, of course, but for my purposes here, what I'm saying is basically correct.) In Chinese there are spaces between characters, but it takes quite a lot of knowledge of the language and often some genuine sleuth work to tell where word boundaries lie; thus it's often trial and error to look up a word. It would be as if English were written thus:
FEAR LESS LY OUT SPOKE N BUT SOME WHAT HUMOR LESS NEW ENG LAND BORN LEAD ACT OR GEORGE MICHAEL SON EX PRESS ED OUT RAGE TO DAY AT THE STALE MATE BE TWEEN MAN AGE MENT AND THE ACT OR 'S UNION BE CAUSE THE STAND OFF HAD SET BACK THE TIME TABLE FOR PRO DUC TION OF HIS PLAY, A ONE MAN SHOW CASE THAT WAS HIS FIRST RUN A WAY BROAD WAY BOX OFFICE SMASH HIT. "THE FIRST A MEND MENT IS AT IS SUE" HE PRO CLAIM ED. "FOR A CENS OR OR AN EDIT OR TO EDIT OR OTHER WISE BLUE PENCIL QUESTION ABLE DIA LOG JUST TO KOW TOW TO RIGHT WING BORN AGAIN BIBLE THUMP ING FRUIT CAKE S IS A DOWN RIGHT DIS GRACE."
查字典还有一个问题来自中文汉字本身的特性。绝大部分语言中词汇之间的分界很明显,有空格在那儿。如果你不懂一个词,那找到该查什么一般不难(当然什么算一个词是个微妙问题,不过在这个话题方面我的说法基本正确)。在中文里呢,汉字之间有空格,但是得需要好多中文知识和真正的侦探本领才能让你找出词汇之间的界限。所以找一个词儿往往是个试错过程。就好象英文写成如下的样子:
FEAR LESS LY OUT SPOKE N BUT SOME WHAT HUMOR LESS NEW ENG LAND BORN LEAD ACT OR GEORGE MICHAEL SON EX PRESS ED OUT RAGE TO DAY AT THE STALE MATE BE TWEEN MAN AGE MENT AND THE ACT OR 'S UNION BE CAUSE THE STAND OFF HAD SET BACK THE TIME TABLE FOR PRO DUC TION OF HIS PLAY, A ONE MAN SHOW CASE THAT WAS HIS FIRST RUN A WAY BROAD WAY BOX OFFICE SMASH HIT. "THE FIRST A MEND MENT IS AT IS SUE" HE PRO CLAIM ED. "FOR A CENS OR OR AN EDIT OR TO EDIT OR OTHER WISE BLUE PENCIL QUESTION ABLE DIA LOG JUST TO KOW TOW TO RIGHT WING BORN AGAIN BIBLE THUMP ING FRUIT CAKE S IS A DOWN RIGHT DIS GRACE.

Imagine how this difference would compound the dictionary look-up difficulties of a non-native speaker of English. The passage is pretty trivial for us to understand, but then we already know English. For them it would often be hard to tell where the word boundaries were supposed to be. So it is, too, with someone trying to learn Chinese.
想象一下这样的情况会怎样加重英文学习者查字典的困难吧。这段话读起来不难,那是因为我们懂英文。对不懂的人来说搞清楚词汇之前的界限可不容易。在学中文的时候情况正是如此。