Albanian was proven to be an Indo-European language in 1854 by the German philologist Franz Bopp. The Albanian language comprises its own branch of the Indo-European language family.
Some scholars believe that Albanian derives from Illyrianwhile others, claim that it derives from Daco-Thracian. (Illyrian and Daco-Thracian, however, may have formed a sprachbund, see Thraco-Illyrian.)
Establishing longer relations, Albanian is often compared to Balto-Slavic on the one hand and Germanic on the other, both of which share a number of isoglosses with Albanian. Moreover, Albanian has undergone a vowel shift in which stressed, long o has fallen to a , much like in the former and opposite the latter. Likewise, Albanian has taken the old relative jos and innovatively used it exclusively to qualify adjectives, much in the way Balto-Slavic has used this word to provide the definite ending of adjectives.