The United Kingdom has no constitutionally defined official language. English is the main language and the de facto official language, and is spoken monolingually by an estimated 95% of the UK population.

However, some nations and regions of the UK have frameworks for the promotion of autochthonous languages. In Wales, English and Welsh are both widely used by government, and Irish and Ulster Scots enjoy limited use alongside English in Northern Ireland, mainly in publicly commissioned translations. Since 2005, the Gaelic Language (Scotland) Act has placed the status of Scottish Gaelic in Scotland on a statutory basis, and the Western Isles region of Scotland has a policy to promote the language.

Under the European Charter for Regional or Minority Languages (which is not legally enforceable) the UK government has committed itself to the promotion of certain linguistic traditions. Welsh, Scottish Gaelic and Cornish are to be developed in Wales, Scotland and Cornwall respectively. Other native languages afforded such protection include Irish in Northern Ireland, Scots in Scotland and Northern Ireland (in the latter territory officially known as Ulster Scots or Ullans, but in the speech of users simply as Scotch or Scots), and British Sign Language.