Classification
The Illyrian languages are part of the Indo-European language family. The relation of the Illyrian languages to other Indo-European languages—ancient and modern—is poorly understood due to the paucity of data and is still being examined. Today, the main source of authoritative information about the Illyrian language consists of a handful of Illyrian words cited in classical sources, and numerous examples of Illyrian anthroponyms, ethnonyms, toponyms and hydronyms.
Given the scarcity of the data it is difficult to identify the sound changes that have taken place in the Illyrian languages; the most widely accepted one is that the Indo-European voiced aspirates /bʰ/, /dʰ/, /gʰ/ became voiced consonants /b/, /d/, /g/.
A grouping of Illyrian with the Messapian language has been proposed for about a century, but remains an unproven hypothesis. The theory is based on classical sources, archaeology and onomastics. Messapian material culture bears a number of similarities to Illyrian material culture. Some Messapian anthroponyms have close Illyrian equivalents.
A grouping of Illyrian with the Venetic language and Liburnian language, once spoken in northeastern Italy and Liburnia respectively, has also been proposed. The consensus now is that Illyrian was quite distinct from Venetic and Liburnian.
Read more about this topic: Illyrian Languages