Paleo-Balkan is a geolinguistic term referring to the Indo-European languages

Indo-European languages

The Indo-European languages are a family of several hundred related languages and dialects, including most major current languages of Europe, the Iranian plateau, and South Asia and also historically predominant in Anatolia...

 that were spoken in the Balkans

Balkans

The Balkans is a geopolitical and cultural region of southeastern Europe...

 in ancient times. Except for Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 and the language that gave rise to Albanian

Albanian language

Albanian is an Indo-European language spoken by approximately 7.6 million people, primarily in Albania and Kosovo but also in other areas of the Balkans in which there is an Albanian population, including western Macedonia, southern Montenegro, southern Serbia and northwestern Greece...

 (see below), they are all extinct, due to Hellenization

Hellenization

Hellenization is a term used to describe the spread of ancient Greek culture, and, to a lesser extent, language. It is mainly used to describe the spread of Hellenistic civilization during the Hellenistic period following the campaigns of Alexander the Great of Macedon...

, Romanization

Romanization (cultural)

Romanization or latinization indicate different historical processes, such as acculturation, integration and assimilation of newly incorporated and peripheral populations by the Roman Republic and the later Roman Empire...

, and Slavicisation

Slavicisation

Slavicisation is a term used to describe a cultural change in which something non-Slavic becomes Slavic. The process can either be voluntary, or applied with varying degrees of force.* Bulgarisation* Croatisation* Czechification* Polonization...

.
The following languages are reported to have been spoken on the Balkan Peninsula by Ancient Greek and Roman writers:

• Ancient Greek
  Ancient Greek
  Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
  
  
• Ancient Macedonian
  Ancient Macedonian language
  Ancient Macedonian was the language of the ancient Macedonians. It was spoken in the kingdom of Macedon during the 1st millennium BCE and it belongs to the Indo-European group of languages...
  
  
• Dacian
  Dacian language
  The extinct Dacian language may have developed from proto-Indo-European in the Carpathian region around 2,500 BC and probably died out by AD 600. In the 1st century AD, it was the predominant language of the ancient regions of Dacia and Moesia and, possibly, of some surrounding regions.It belonged...
  
  
• Illyrian
  Illyrian languages
  The Illyrian languages are a group of Indo-European languages that were spoken in the western part of the Balkans in former times by groups identified as Illyrians: Ardiaei, Delmatae, Pannonii, Autariates, Taulanti...
  
  
• Liburnian
  Liburnian language
  The Liburnian language is an extinct language which was spoken by the ancient Liburnians, who occupied Liburnia in classical times. The Liburnian language is reckoned as an Indo-European language, in the Centum group. Alternative speculations place it on the same Indo-European branch as the Venetic...
  
  
• Messapic
  Messapian language
  Messapian is an extinct Indo-European language of South-eastern Italy, once spoken in the region of Apulia. It was spoken by the three Iapygian tribes of the region: the Messapians, the Dauni and the Peucetii....
  
  
• Paeonian
• Phrygian
  Phrygian language
  The Phrygian language was the Indo-European language of the Phrygians, spoken in Asia Minor during Classical Antiquity .Phrygian is considered to have been closely related to Greek....
  
  
• Thracian
  Thracian language
  The Thracian language was the Indo-European language spoken in ancient times in Southeastern Europe by the Thracians, the northern neighbors of the Ancient Greeks. The Thracian language exhibits satemization: it either belonged to the Satem group of Indo-European languages or it was strongly...
  
  
• Venetic
  Venetic language
  Venetic is an extinct Indo-European language that was spoken in ancient times in the North East of Italy and part of modern Slovenia, between the Po River delta and the southern fringe of the Alps....
  
  

Although these languages are all members of the Indo-European language family, the relationships between them are unknown.