Chinese is a tonal language: in Chinese, tones convey meaning, rather than (or in addition to) what the speaker wants to emphasize. The same sound with different tones can have a completely different meaning. (For that matter, the same sound with the same tones can also have different meanings, but let’s not talk about that.) Speaking a tonal language is a great way to be reminded that when your friends and family in America call your singing “tone-deaf,” they might have actually been on to something.
Although the concept of tones is a daunting concept to people who are wildly afraid of even thinking about learning Chinese, keeping track of your tones is important. Choosing the right tones can have a distinct effect on whether the person you are talking to thinks you are a crazy person or not a crazy person, which can be a useful distinction.
Without further ado, the importance of tones, explained in three examples:
经济 (jing1 ji4, meaning: the economy) — something I know a lot about
竞技 （jing4 ji4, meaning: sports) — something I don’t know a lot about
笑话 （xiao4 hua4, meaning: jokes) — something I spend too much time thinking about
消化 (xiao1 hua4, meaning: digestion) — something my mother spends too much time thinking about
小偷 （xiao3 tou1, meaning: thief) — something that does not describe me
小头 (xiao3 tou2, meaning: small head) — something that describes me very well
As should be clear, these clarifications are frequent occurrences in my life. Whether I am a crazy person or not a crazy person is still unclear, however.