Query: Where is Catalan the only official language?
Context: Catalan (/ˈkætəlæn/; autonym: català [kətəˈla] or [kataˈla]) is a Romance language named for its origins in Catalonia, in what is northeastern Spain and adjoining parts of France. It is the national and only official language of Andorra, and a co-official language of the Spanish autonomous communities of Catalonia, the Balearic Islands, and Valencia (where the language is known as Valencian, and there exist regional standards). It also has semi-official status in the city of Alghero on the Italian island of Sardinia.