The United Nations' series of "language days" are designed to promote the use of the six official languages of the UN as well as to celebrate cultural and linguistic diversity (语言多样性). Chinese Language Day is the 20th April. It's a time chosen to fit in with the Chinese of Guyu (古语), which honours Cangjie—the four-eyed  figure who is traditionally understood to have created Chinese characters in the time of the Yellow Emperor, 5000 years ago.

    Mandarin (普通话) is the most-spoken language in the world, with over 1.5 billion speakers. When most people think of "Chinese", it is Mandarin that they are . But Mandarin Chinese is far from the only variant of the Chinese language—or the only language spoken in China. In fact, there are a great number of Chinese languages. Remember—this is a country which is both very large and very, very old. Different regions are within the  expanse of territory, that is, China can be  not only by great distances but also by broadly geographical features such as mountain ranges.

    It is hard to guess how many dialects actually exist. In general, dialects can be  classified into one of the seven large groups: Putonghua (Mandarin), Gan, Kejia (Hakka), Min, Wu, Xiang, and Yue (Cantonese). Each language group contains a large number of dialects.

    Understanding the situation is  by the fact that, while many Chinese people in different geographical areas of the country may not understand each other when they speak their regional dialect, they may share the same written language even if their pronunciation of different characters within that language may.

A  feature across all Chinese languages is tone. For instance, Mandarin has four tones and Cantonese has six tones. Tone, in terms of language, is the pitch (音高) in which syllables (音节) in words are spoken. In Chinese, different words  different keys. Some words even have pitch variations in one single syllable.