As we all know, China is a large country. That is the reason why there are so many different dialects in China. It is hard to guess how many dialects actually exist. In general, dialects can be roughly classified into the following seven large groups: Putonghua (Mandarin), Gan, Kejia (Hakka), Min, Wu, Xiang. and Yue (Cantonese). Each language group contains a large number of dialects. These are the Chinese languages spoken mostly by the Han people, which represents about 92 percent of the total population. The rest are non-Chinese languages spoken by minorities in China, such as Tibetan, Mongolian and Miao.
Even though the dialects from the seven groups are quite different, a non-Mandarin speaker usually can speak some Mandarin, even if with a strong accent. This is largely because Mandarin has been the official national language since 1913.
Despite the large differences among Chinese dialects, there is one thing in common-they all share the same writing system based on Chinese characters. However, the same character is pronounced differently depending on which dialect one speaks. Let's take "wo" for example, the word for "I" or "me". In Mandarin, it is pronounced "wo". In Wu, it is pronounced "ngu". In Min, "gua". In Cantonese, "ngo". You get the idea.
A distinguishing (显著的)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 pronounced. In Chinese, different words stress different pitches. Some words even have the pitch variation in one single syllable so they have different tones and pronunciation. Thus, the tone is very important in any Chinese dialect. There are many cases when words spelt in pinyin are the same, but the way it is pronounced changes the meaning. For example, in Mandarin, 妈 (ma)means mother, 马 (ma)means horse, and 骂 (ma)means to scold.