What is the 'stated' purpose of designating an official language for a country?

An official language, also called state language, is a language given a special 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).[1] The term "official language" does not typically refer to the language used by a people or country, but by its government.[2][3]

178 countries of the world recognize an official language, 101 of them recognizing more than one. The government of Italy officialised Italian only in 1999,[4] and some nations (such as the United States) have never declared official languages at the national level.[5] 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."[5]

Many of the world's constitutions mention one or more official or national languages.[6][7] 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.