The Dacians occupied what is now Rumania when first recorded. They belong to a group of peoples attested in the Balkans which comprised the Dacians, the Illyrians, the Getae and the Thracians. None have left any substantial linguistic heritage. These languages are only known from inscriptions, contemporary glosses (mainly to Greek) and onomastic data. About twenty-five reliable indo-European etymologies have been established for Dacian.

Dacian and Thracian may have been two separate languages or distinct dialects of the same language. Earlier than 3000 B.C.E in the Balkans there is a sharp cultural discontinuity which is seen by many as caused by intruders speaking the proto-Indo-European, or an early descendant. Mixture with the languages of the existing population then led to the genesis of the major languages found in the Balkans historically.

The Dacian-Mysian language region can be determined from the occurrence of the word "dava" meaning town.

dacian_thracian This word is found mostly in Rumania (which is therefore the centre of its diffusion) and less frequently in Bulgaria, the Dobruja and Serbia. The word is not found in Thrace proper indicating that Thracian was distinct from Daco-Mysian. A differentiator for Thracian is "para", meaning river, which occurs widely and frequently in Thrace but very rarely in the Daco-Mysian region. Thus the onomastic evidence points to Daco-Mysian and Thracian being two distinct languages.