By the late imperial period, local varieties of Chinese had diverged to the extent that people from different provinces could not understand one another. In order to facilitate communication between officials from different provinces, and between officials and the inhabitants of the areas to which they were posted, imperial administrations adopted a
koiné based on various northern dialects. Until well into the 19th century, this language was based on dialects spoken in the area of
Nanjing, the first Ming capital and a major cultural centre, though not identical to any single dialect. The standard language of the Ming and early Qing, when it was based on lower Yangtze dialects, is sometimes called
Middle Mandarin. In 1375, the
Hongwu Emperor commissioned a dictionary known as the () intended to give a standard pronunciation. The dictionary was unsuccessful, criticised on one side for departing from the tradition of the
Song dynasty rime dictionaries and
rime tables, and on the other for not accurately reflecting the contemporary standard of elegant speech. The Korean scholar
Sin Sukchu published the ( "Correct Rhymes from the Hongwu Reign with Korean Translation and Commentaries") in 1455, augmenting the by giving the Chinese pronunciation of each word using the newly created
Hangul alphabet. In addition to these "standard readings", he recorded a rather different body of "popular readings", some of which are also preserved in the works of
Ch'oe Sejin. Kim Kwangjo, in his extensive study of these materials, concluded that Sin's standard readings constitute an idealized
phonology of the earlier dictionary, while the popular readings reflect contemporary speech. In contrast, Yùchí Zhìpíng and
Weldon South Coblin hold that the two readings reflect different versions of 15th-century standard speech. The term (), or "language of the officials", first appeared in Chinese sources in the mid-16th century. Later in that century, the
Jesuit missionary
Matteo Ricci used the term in his diary: The missionaries recognized the utility of this standard language, and embarked on its study. They translated the term into European languages as (Portuguese) and (Spanish), meaning the language of the
mandarins, or imperial officials. Ricci and
Michele Ruggieri published a Portuguese-Mandarin dictionary in the 1580s.
Nicolas Trigault's guide to Mandarin pronunciation was published in 1626. Grammars of Mandarin were produced by
Francisco Varo (finished in 1672 but not printed until 1703) and
Joseph Prémare (1730). In 1728, the
Yongzheng Emperor, unable to understand the accents of officials from
Guangdong and
Fujian, issued a decree requiring the governors of those provinces to provide for the teaching of proper pronunciation. Although the resulting Academies for Correct Pronunciation (, ) were short-lived, the decree did spawn a number of textbooks that give some insight into the ideal pronunciation. Although
Beijing had become the capital in 1420, its speech did not rival the prestige of the Nanjing-based standard until the middle of the Qing dynasty. As late as 1815,
Robert Morrison based the first English–Chinese dictionary on the lower Yangtze koiné as the standard of the time, though he conceded that the Beijing dialect was gaining in influence. By the middle of the 19th century, the Beijing dialect had become dominant and was essential for any business with the imperial court. The new standard was described in grammars produced by
Joseph Edkins (1864),
Thomas Wade (1867) and
Herbert Giles (1873). In the early 20th century, reformers decided that China needed a national language. The traditional written form,
Literary Chinese, was replaced with
written vernacular Chinese, which drew its vocabulary and grammar from a range of
Northern dialects (now known as Mandarin dialects). After unsuccessful attempts to define a cross-dialectal spoken standard, it was realized that a single spoken form must be selected. The only realistic candidate was the Beijing-based , which was adapted and developed into modern
Standard Chinese, which is also often called Mandarin. == Phonology ==