Today, Occitan is an official language in Catalonia, where a subdialect of Gascon known as Aranese is spoken in the Val d'Aran. Occitan's closest relative is Catalan. Since September 2010, the Parliament of Catalonia has considered Aranese Occitan to be the officially preferred language for use in the Val d'Aran.
Across history, the terms Limousin (Lemosin), Languedocien (Lengadocian), Gascon, and later Provençal (Provençal, Provençau or Prouvençau) have been used as synonyms for the whole of Occitan; nowadays, "Provençal" is understood mainly as the Occitan dialect spoken in Provence, in southeast France.
Unlike other Romance languages such as French or Spanish, there is no single written standard language called "Occitan", and Occitan has no official status in France, home to most of Occitania. Instead, there are competing norms for writing Occitan, some of which attempt to be pan-dialectal, whereas others are based on particular dialects. These efforts are hindered by the rapidly declining use of Occitan as a spoken language in much of southern France, as well as by the significant differences in phonology and vocabulary between different Occitan dialects.
In particular, the northern and easternmost dialects have more morphological and phonetic features in common with the Gallo-Italic and Oïl languages (e.g. nasal vowels; loss of final consonants; initial cha/ja- instead of ca/ga-; uvular ⟨r⟩; the front-rounded sound /ø/ instead of a diphthong, /w/ instead of /l/ before a consonant), whereas the southernmost dialects have more features in common with the Ibero-Romance languages (e.g. betacism; voiced fricatives between vowels in place of voiced stops; -ch- in place of -it-), and Gascon has a number of unusual features not seen in other dialects (e.g. /h/ in place of /f/; loss of /n/ between vowels; intervocalic -r- and final -t/ch in place of medieval -ll-). There are also significant lexical differences, where some dialects have words cognate with French, and others have Catalan and Spanish cognates (maison/casa "house", testa/cap "head", petit/pichon "small", achaptar/crompar "to buy", entendre/ausir "to hear", se taire/se calar "to be quiet", tombar/caire "to fall", p(l)us/mai "more", totjorn/sempre "always", etc.). Nonetheless, there is a significant amount of mutual intelligibility.
The long-term survival of Occitan is in grave doubt. According to the UNESCO Red Book of Endangered Languages, four of the six major dialects of Occitan (Provençal, Auvergnat, Limousin and Languedocien) are considered severely endangered, whereas the remaining two (Gascon and Vivaro-Alpine) are considered definitely endangered.