That Albanian is of clearly Indo-European origin was recognized by the German philologist, Franz Bopp, in 1854; the details of the main correspondences of Albanian with Indo-European languages were elaborated by another German philologist, Gustav Meyer, in the 1880s and 1890s. Further linguistic refinements were presented by the Danish linguist Holger Pedersen and the Austrian Norbert Jokl. The following etymologies illustrate the relationship of Albanian to Indo-European (an asterisk preceding a word denotes an unattested, hypothetical Indo-European parent word, which is written in a conventionalized orthography): pes' "five" (from *pZnk e); zjarm "fire" (from *g hermos); nat' "night" (from *nok t-); dh'nd'r "son-in-law" (from * gem ter-); gjarp'r "snake" (from *sZrpon-); bjer "bring!" (from *bhere); djeg "I burn" (from *dheg ho); kam "I have" (from *kapmi); pata "I had" (from *pot-); pjek "I roast" (from * peko); thom, thot' "I say, he says" (from *k'emi, *k'et . . .).

The verb system includes many archaic traits, such as the retention of distinct active and middle personal endings (as in Greek) and the change of a stem vowel e in the present to o (from *e) in the past tense, a feature shared with the Baltic languages. For example, there is mbledh "gathers (transitive)" as well as mblidhet "gathers (intransitive), is gathered" in the present tense, and mblodha "I gathered" with an o in the past. Because of the superficial changes in the phonetic shape of the language over 3,000 years and because of the borrowing of words from neighbouring cultures, the continuity of the Indo-European heritage in Albanian has been underrated.

Albanian shows no obvious close affinity to any other Indo-European language; it is plainly the sole modern survivor of its own subgroup. Of ancient languages, both Dacian (or Daco-Mysian) and Illyrian have been tentatively considered its ancestor or nearest relative.