language spoken in the county of Cornwall. Historically, the main language of Cornwall was Cornish. By 1800, Cornish was endangered with some debate about a mythical last speaker of the Cornish language. Revival of the Cornish language and some recognition has occurred in the 20th century. United States In the United States, English (American English) is the national language only in an informal sense, by numbers and by historical and contemporary association. The United States Constitution does not explicitly declare any official language, although the constitution is written in English, as is all federal legislation. , Representative Peter T. King introduced H.R.997, the English Language Unity Act of 2015, in the United States House of Representatives. This bill would establish English as the official language of the United States. A companion bill, S.678, was introduced by Senator Jim Inhofe in the United States Senate on 9 March 2015. Both bills were referred to committee. Similar legislation has been introduced every year since 1973. Vietnam In Vietnam, the Vietnamese language had been the de facto national language for many years, but it was not until Decree No. 5 of the 2013 constitution that the Vietnamese language was officially described as the National Language. See also Ethnolect Indigenous language Language policy Regional language Standard language Official language Working language Bengali language movement in Bangladesh Anti-Hindi agitations of Tamil Nadu, India Global language system Notes and references Language varieties and styles Politics by issue Culture by region Linguistic rights Concepts in language policy