Just as in English, words in Chinese are the basic element for a sentence. Words (with no space in between) plus punctuation form a normal sentence in Chinese. In English, the length of words varies from one letter to over ten letters; there is not a clue to trace the meanings' relevance to the length of the words.
In all types of Chinese, the most often used length of words varies from one to four. Simpler words usually start with less characters and expand to more characters when the meaning is needed. For example, in Chinese, the word “I” or “me” is written as “我[wǒ]”; it is a simple one-character word. Nevertheless, the character for “we” or “us” is written as “我们[wǒ men]”. In English, they are written totally differently, although you know the inherent connection between those words. In Chinese, instead of memorizing the different pronunciation on individual words like in English, the combinations of different characters are the key to the Chinese language both in its writing and speaking aspects.
Chinese would be an easy language if every word could be built by the characters you know. There are certain combinations of characters you may find bizarre, or that don't make sense based on your understanding. For example, the word “gasoline” in Chinese is written as “汽油[qì yóu]”. The second character “油[yóu]” means “oil”, which makes sense for its existence in the combination. But the first character “汽[qì]” means “steam”, which makes learners confused about the combination. Another weird combination is the word “小说”([xiǎo shuō], novel) translated into Chinese, which is the combination of the characters “小” ([xiǎo], little) plus “说” ([shuō], talk).
The category of three-character combination words is the best representative of the building phenomenon mentioned earlier. For example, the word “三轮车”([sān lún chē], tricycle) in Chinese is combined with the characters: “三”([sān], three), “轮”([lún], wheel) and “车”([chē], vehicle). And the word “收音机”([shōu yīn jī], radio) in Chinese is combined with three characters: “收”([shōu], receive), “音”([yīn], sound) and “机”([jī], machine).
The commonly used four-character words are mostly Chengyu, which came from historical stories. They are a type of traditional Chinese idiomatic expressions, used when expressing similarity between the current situation and a Chengyu story. Chengyu were widely used in classical Chinese and are still very common in Chinese writing. There are about thousands of Chengyu in the Chinese language, and usually only high-level learners of Chinese are capable using them correctly. Also, for local speakers, people who use Chengyu often in their speech are considered well educated.
Bamboo — The character bamboo kept its basic shape from beginning to nowadays. The essence of the meaning is well conveyed by the character.
Tiger — Unlike the character bamboo, the character tiger experienced big changes throughout history. It is also very interesting to see the oracle bones tiger character literally looks like an animal horizontally. That is a perfect example of pictographic characters.
Baby — The character baby is very like the form of baby at the stage of oracle bones. After thousands of years evolution, the basic form of the character has not been changed so much.