 National governments have historically viewed linguistic diversity as an economic, administrative or military liability, as well as a potential source of separatist movements; therefore, they have generally fought to eliminate it, by extensively promoting the use of the official language, restricting the use of the other languages in the media, recognizing them as mere "dialects", or even persecuting them.As a result, all of these languages are considered endangered to varying degrees according to the UNESCO Red Book of Endangered Languages, ranging from "vulnerable" (e.g.Sicilian and Venetian) to "severely endangered" (Arpitan, most of the Occitan varieties).