An official language, also called state language, is a language given a special legal status in a particular country, state, or other jurisdiction. Typically a country's official language refers to the language used in government (judiciary, legislature, administration). The term "official language" does not typically refer to the language used by a people or country, but by its government,  as "the means of expression of a people cannot be changed by any law".
About half the countries of the world have declared one or more official languages. The government of Italy officialised Italian only in 1999, and some nations (such as the United States) have never declared official languages at the national level. Other nations have declared non-indigenous official languages. "The Philippines and parts of Africa live with a peculiar cultural paradox. Although the official languages [in Africa] may be French or English, these are not the languages most widely spoken by [the country's] residents."
Worldwide, 178 countries have at least one official language, and 101 of these countries recognise more than one language. Many of the world's constitutions mention one or more official or national languages. Some countries use the official language designation to empower indigenous groups by giving them access to the government in their native languages. In countries that do not formally designate an official language, a de facto national language usually evolves. English is the most common official language, with recognized status in 51 countries. Arabic, French, and Spanish are also widely recognized.
An official language that is also an indigenous language is called endoglossic, one that is not indigenous is exoglossic. An instance is Nigeria which has three endoglossic official languages. By this the country aims to protect the indigenous languages although at the same time recognising the English language as its lingua franca.
Around 500 BC, when Darius the Great annexed Mesopotamia to the Persian Empire, he chose a form of the Aramaic language (the so-called Official Aramaic or Imperial Aramaic) as the vehicle for written communication between the different regions of the vast empire with its different peoples and languages. Aramaic script was widely employed from Egypt in the southwest to Bactria and Sogdiana in the northeast. Texts were dictated in the native dialects and written down in Aramaic, and then read out again in the native language at the places they were received.
The First Emperor of Qin standardized the written language of China after unifying the country in 221 BC. Classical Chinese would remain the standard written language for the next 2000 years. Standardization of the spoken language received less political attention, and Mandarin developed on an ad hoc basis from the dialects of the various imperial capitals until being officially standardized in the early twentieth century.