The Mandarin language has a fundamental difference from Western languages: it is tonal. Tones are one of the biggest challenges for Mandarin learners, but their mastery is essential. Incorrect tones can make your spoken Mandarin difficult or impossible to understand, but using the correct tones will allow you to express yourself clearly.
Mandarin tones are especially difficult for speakers of Western languages. English, for example, uses tones for inflection, but this is a very different usage from Mandarin. Rising tones in English often imply a question or sarcasm. Falling tones may be used for emphasis. Changing the tones of a Mandarin sentence, though, could completely change the meaning.
Let’s take an example. Suppose you are reading a book and your brother (or sister or child) keeps on interrupting you. You are likely to become exasperated and say “I’m trying to read a book!” In English, this would be said with an emphatic falling tone at the end.
But if you use a falling tone in Mandarin, the meaning completely changes.
The second version of this sentence would have your listeners scratching their heads.
So practice your tones! They are essential for speaking and understanding Mandarin.