The European Charter for Regional or Minority Languages is a European convention (CETS 148) adopted in 1992 under the auspices of the Council of Europe to protect and promote historical regional and minority languages in Europe. It only applies to languages traditionally used by the nationals of the State Parties (thus excluding languages used by recent immigrants from other states), which significantly differ from the majority or official language (thus excluding mere local dialects of the official or majority language) and which either have a territorial basis (and are therefore traditionally spoken by populations of regions or areas within the State) or are used by linguistic minorities within the State as a whole (thereby including such languages as Yiddish and Romany, which were used over a wide geographic area).
Languages which are official within regions or provinces or federal units within a State (for example Catalan in Spain) are not classified as official languages of the State and may therefore benefit from the Charter. On the other hand, the Republic of Ireland has not been able to sign the Charter on behalf of the Irish language (although a minority language) as it is defined as the first official language of the state. The United Kingdom has, though, ratified the Charter in respect of (among other languages) Irish in Northern Ireland. France, although a signatory, has been constitutionally blocked from ratifying the Charter in respect of the languages of France.
The charter provides a large number of different actions state parties can take to protect and promote historical regional and minority languages. There are two levels of protection - all signatories must apply the lower level of protection to qualifying languages; signatories may further declare that a qualifying language or languages will benefit from the higher level of protection which lists a range of actions from which states must agree to undertake at least thirty-five.