Radoslav Katicic, one of the leading authorities on the ancient languages of the Balkans, argued that key Albanian toponyms—Lesh, Drisht, Drin and Mat—can be derived from their ancient forms only through Albanian-specific sound changes. No other language’s sound laws produce them. And where Illyrian glosses survive at all, he found Albanian correspondences “remarkably easy to find.”

Cited:

“Addressing claims that Albanian toponyms show non-Albanian mediation, Katičić writes: “Main Albanian names such as Lesh, Drisht, Kunavja, Drin, Buenë, Mat, and Ishm can be derived from their ancient forms Lissus, Drivastum, Candavia, Drinus, Barbanna, Mathis, and Isamnus only by Albanian sound changes, and by no others. … And for the few preserved Illyrian glosses it is remarkably easy to find Albanian correspondences. Nothing in the nature of a proof has been presented so far for the Thracian origin of Albanian.”

Source

Katičić, Radoslav. Ancient Languages of the Balkans. Part One. The Hague: Mouton, 1976.