In Chinese linguistics, Mandarin (simplified Chinese: 官话; traditional Chinese: 官話; pinyin: Guānhuà; literally "speech of officials") is a group of related varieties or dialects spoken across most of northern and southwestern China. Because most Mandarin dialects are found in the north, the group is also referred to, particularly among Chinese speakers, as the "northern dialect(s)" (simplified Chinese: 北方话; traditional Chinese: 北方 話; pinyin: Běifānghuà). When the Mandarin group is taken as one language, as is often done in academic literature, it has more native speakers (nearly a billion) than any other language.
A northeastern-dialect speaker and a southwestern-dialect speaker can hardly communicate except through the standard language, mainly because of the differences in tone. Nonetheless, the variation within Mandarin is less significant than the much greater variation found within several other varieties of Chinese; this is thought to be due to a relatively recent spread of Mandarin across China, combined with a greater ease of travel and communication compared to the more mountainous south of China.