An official language is a language that is given a special legal status in a particular country, state, or other jurisdiction. Typically a country's official language refers to the language used within government (e.g., courts, parliament, administration). Since "the means of expression of a people cannot be changed by any law", the term "official language" does not typically refer to the language used by a people or country, but by its government.
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.