Also, if somebody showed you a page of English text written a thousand years ago, it would look like gibberish. Even our alphabets are somewhat different. If you were from China and I showed you a page of Chinese text from a thousand years ago, you'd be able to read it without much problem. Written Chinese just hasn't changed much. I would guess it has to do with the fact that our written language is directly related to how we pronounce words, and theirs isn't. That and it's a lot easier for foreign influences to change a language when the language is trapped on a tiny island.
Also, ever wonder how or if people in China text each other, what with a 5,000 character alphabet? Apparently, you type the first three roman letters of the phonetic pronunciation of a character, then select the character from a list of characters that start out being pronounced that way.
Edit: A friend commented with a correction - since most people in China learn simplified characters these days, the task of reading an ancient text would be possible, but by no means effortless. I stand corrected.