Chinese (simplified Chinese: 汉语; traditional Chinese: 漢語; pinyin: Hànyǔ; literally: 'Han language'; or especially though not exclusively for written Chinese: 中文; Zhōngwén; 'Chinese writing') is a group of languages that forms the Sinitic branch of the Sino-Tibetan languages. Chinese languages are spoken by the ethnic Chinese majority and many minority ethnic groups in China. About 1.2 billion people (around 16% of the world's population) speak some form of Chinese as their first language. The varieties of Chinese are usually considered by native speakers to be regional variants of ethnic Chinese speech, without consideration of whether they are mutually intelligible. Due to their lack of mutual intelligibility, linguists generally describe them as distinct languages, perhaps hundreds, sometimes noting that they are more varied than the Romance languages. Investigation of the historical relationships among the Sinitic languages is just getting started. Currently, most classifications posit 7 to 13 main regional groups, based on often superficial phonetic developments, of which the most populous by far is Mandarin (about 800 million speakers, e.g. Southwestern Mandarin), followed by Min (75 million, e.g. Southern Min), Wu (74 million, e.g. Shanghainese), Yue (68 million, e.g. Cantonese). These groups are unintelligible to each other, and generally many of their subgroups are mutually unintelligible as well (e.g., not only is Min Chinese a family of mutually unintelligible languages, but Southern Min itself is not a single language). There are, however, several transitional areas, where languages and dialects from different branches share enough features for some limited intelligibility between neighboring areas. Examples are New Xiang and Southwest Mandarin, Xuanzhou Wu and Lower Yangtze Mandarin, Jin and Central Plains Mandarin, and certain divergent dialects of Hakka with Gan (though these are unintelligible with mainstream Hakka). All varieties of Chinese are tonal to at least some degree and largely analytic. Standard Chinese (Pǔtōnghuà/Guóyǔ/Huáyǔ) is a standardized form of spoken Chinese based on the Beijing dialect of Mandarin. It is an official language of China, similar to one of the national languages of Taiwan (Taiwanese Mandarin) and one of the four official languages of Singapore. It is one of the six official languages of the United Nations. The written form of the standard language (中文; Zhōngwén), based on the logograms known as Chinese characters (汉字/漢字; Hànzì), is shared by literate speakers of otherwise unintelligible dialects. The earliest Chinese written records are Shang dynasty-era oracle inscriptions, which can be traced back to 1250 BCE. The phonetic categories of Archaic Chinese can be reconstructed from the rhymes of ancient poetry. During the Northern and Southern dynasties period, Middle Chinese went through several sound changes and split into several varieties following prolonged geographic and political separation. Qieyun, a rime dictionary, recorded a compromise between the pronunciations of different regions. The royal courts of the Ming and early Qing dynasties operated using a koiné language (Guanhua) based on Nanjing dialect of Lower Yangtze Mandarin. Standard Chinese was adopted in the 1930s, and is now an official language of both the People's Republic of China and the Republic of China on Taiwan.