stylistic:tone
Linguistic affiliation

The Dacians and Getae were always considered as Thracians by the ancients (Dio Cassius, Trogus Pompeius, Appian, Strabo and Pliny the Elder), and were both said to speak the same Thracian language. The linguistic affiliation of Dacian is uncertain, since the ancient Indo-European language in question became extinct and left very limited traces, usually in the form of place names, plant names and personal names. Thraco-Dacian (or Thracian and Daco-Mysian) seems to belong to the eastern (satem) group of Indo-European languages. There are two contradictory theories: some scholars (such as Tomaschek 1883; Russu 1967; Solta 1980; Crossland 1982; Vraciu 1980) consider Dacian to be a Thracian language or a dialect thereof. This view is supported by R. G. Solta, who says that Thracian and Dacian are very closely related languages. Other scholars (such as Georgiev 1965, Duridanov 1976) consider that Thracian and Dacian are two different and specific Indo-European languages which cannot be reduced to a common language. Linguists such as Polomé and Katičić expressed reservations about both theories.

The Dacians are generally considered to have been Thracian speakers, representing a cultural continuity from earlier Iron Age communities loosely termed Getic, Since in one interpretation, Dacian is a variety of Thracian, for the reasons of convenience, the generic term ‘Daco-Thracian" is used, with "Dacian" reserved for the language or dialect that was spoken north of Danube, in present-day Romania and eastern Hungary, and "Thracian" for the variety spoken south of the Danube. There is no doubt that the Thracian language was related to the Dacian language which was spoken in what is today Romania, before some of that area was occupied by the Romans. Also, both Thracian and Dacian have one of the main satem characteristic changes of Indo-European language, *k and *g to *s and *z. With regard to the term "Getic" (Getae), even though attempts have been made to distinguish between Dacian and Getic, there seems no compelling reason to disregard the view of the Greek geographer Strabo that the Daci and the Getae, Thracian tribes dwelling north of the Danube (the Daci in the west of the area and the Getae further east), were one and the same people and spoke the same language.

Another variety that has sometimes been recognized is that of Moesian (or Mysian) for the language of an intermediate area immediately to the south of Danube in Serbia, Bulgaria and Romanian Dobruja: this and the dialects north of the Danube have been grouped together as Daco-Moesian. The language of the indigenous population has left hardly any trace in the anthroponymy of Moesia, but the toponymy indicates that the Moesii on the south bank of the Danube, north of the Haemus Mountains, and the Triballi in the valley of the Morava, shared a number of characteristic linguistic features with the Dacii south of the Carpathians and the Getae in the Wallachian plain, which sets them apart from the Thracians though their languages are undoubtedly related.

Dacian culture is mostly followed through Roman sources. Ample evidence suggests that they were a regional power in and around the city of Sarmizegetusa. Sarmizegetusa was their political and spiritual capital. The ruined city lies high in the mountains of central Romania.

Vladimir Georgiev disputes that Dacian and Thracian were closely related for various reasons, most notably that Dacian and Moesian town names commonly end with the suffix - DAVA, while towns in Thrace proper (i.e. South of the Balkan mountains) generally end in -PARA (see Dacian language). According to Georgiev, the language spoken by the ethnic Dacians should be classified as "Daco-Moesian" and regarded as distinct from Thracian. Georgiev also claimed that names from approximately Roman Dacia and Moesia show different and generally less extensive changes in Indo-European consonants and vowels than those found in Thrace itself. However, the evidence seems to indicate divergence of a Thraco-Dacian language into northern and southern groups of dialects, not so different as to qualify as separate languages. Polomé considers that such lexical differentiation (-dava vs. para) would, however, be hardly enough evidence to separate Daco-Moesian from Thracian.