Tone is also called word tone. Tone, as a phoneme to distinguish meaning, mainly appears in Sino-Tibetan and African languages (some people think that Swedish also has tones), and the number ranges from two (Pumi) to more than nine (Cantonese). There are four tones in modern Mandarin Chinese, and the tone values are 55, 35, 2 14, 5 1 respectively.

In fact, any pronunciation can't be without tone sandhi, but in non-tonal language, the different tones will not affect the meaning of words.