Part of the reason is because many Chinese words can be used as either noun, verb, adjective or even adverb, especially compound words with no change of form in itself. As to what exact role it is playing in the sentence largely depends on the context and the words surround it. It’s not easy to define a Chinese word as just noun or verb or anything else. You have to look at it in the context.
Another reason is that a big part of grammatical rules in English or other alphabetical languages can be replaced by long compound words or phrases in Chinese easily. Therefore, rules are not that terribly needed. It’s just like using lots of self made compound English phrase to shorten the sentence. For example:
我喜欢那双"一踩就会发光发声的"鞋子。 Wǒ xǐhuan nà shuāng "yī cǎi jiù huì fāguāng fā shēng de" xiézi. I like that stomp-then-flash-and-sing shoe.
See? Do you need to care much on grammar rules for “stomp-then-flash-and-sing? :-)
The other reason includes the habit of saying for no reason. The sentence pattern may or may not make sense to you but no Chinese will misunderstand it if it is said in the right pattern. If you turn it into something reasonable to you, it’s possible no Chinese will understand it. This kind of pattern you just need to memorize as the way it is.
Many thanks to Grace from Just Learn Chinese for this guest post.