I have translated this small part of a book from A. Stipcevic about Illyrians. Since i could not find version issued in English language. Its Chapter two, about Illyrian remains in Balkans.

Illyrians, history, life and culture. Second version issued in 1989 in Zagreb.

Chapter II, Illyrian remains in Balkans after downfall of antique civilizations

Only recently science can give us answer on one another question that is very important about the subject that we are debating - the question about the relationship of old Illyrians and modern Albanians. Many experts today consider that it is proven that Albanians are the only Balkan people that are directly decedent from ancient Illyrians. Protected by the high and unreachable mountains and far from the roads which were used by barbarians in the time of big migrations of people, these last remains of Illyrians were preserved in many elements of spiritual and material culture of their distant relatives. Thesis that Albanians are remains of Illyrians was first time clearly formulated by German historian Johannes Thunmann in XVIII. cet. (1) He was claiming that it's historically impossible to prove any ethnic migration to territory of modern Albania from ancient times till today, Thunmann concludes that, judging by everything, people that live there today, lived on that territory since ancient times. This thesis were supported and accepted by many other historians. Among the first it was Slovenian historian and writer A. T. Linhart who claims that Illyrian language fully lives today, even though not that pure, in Albanian mountains (und noch heute, obwohl nicht mehr rein, in den Gebirge albaniens lebt) (2). But all of this was only guessing based on theory, but not opinions based on the scientific facts. The first one who will give scientific base to these thesis was an Austrian Georg von Hahn, major expert in Albanian history and Albanian language, all of his conclusions about autochthony of Albanians, he augmented with scientific facts.(3). Not denying old Balkan origin of Albanians, many historians and linguists in XIV. and XX. century suggested different solutions for the question of Albanian origin. By some of them, Albanians are descendants of Thracians (Karl Pauli, Gustav Weigand, Dimitar Dečev), by the others, from Dakomezians (Vladimir Georgijev) etc. But results that were achieved by the different scientific disciplines, especially in the few last years, have foreshadow many of these old doubts about this important question in paleobalkanistics. These researches have confirmed thesis that were brought two centuries before by the Thunmann(4). Linguists were the hardest ones to accept these thesis before but also sometimes today. They will contribute to the mess that was present for the long time in the scientific circles about this issue. Today linguists mostly agree that it can't be proven with high certainty that Albanian language is remain of Illyrian one, because Illyrian is too unknown so there could be grammatical and lexical comparison between them, but analysis of onomastic and toponomastic definition gave enough evidence to support thesis about direct origin of Albanian language from Illyrian language and to make it most plausible.
Furthermore A. Stipcevic says:
Other scientific areas have in many ways also contributed in claiming continuity of ancient Illyrians to modern Albanians. So archaeologists have played major role researching material culture of Early Middle Ages, where they have concluded that there is no interruption in continuity from the ancient Illyrian times to Early Medieval time. And that many artifacts found in necropolis from VII century and VIII century (Kalaja Dalmaçes, Kruja, etc) typologically connect with Illyrian ancient historical culture. Then there Stipcevic mentions Ethnologists who while researching extremely rich Albanian and still not enough explored ethnographic structure, they found plenty of various elements that directly derive from ancient Illyrian cultural heritage.
there is continuity and similarity found in ornaments and religious symbolic, folk dance, music, anthroponymy, toponymy,,