The Thracian language is an extinct and poorly attested language, spoken in ancient times in Southeast Europe by the Thracians. The linguistic affinities of the Thracian language are poorly understood, but it is generally agreed that it was an Indo-European language.
The point at which Thracian became extinct is a matter of dispute. However, it is generally accepted that Thracian was still in use in the 6th century AD: Antoninus of Piacenza wrote in 570 that there was a monastery in the Sinai, at which the monks spoke Greek, Latin, Syriac, Egyptian, and Bessian – a Thracian dialect.
A classification put forward by Harvey Mayer, suggests that Thracian (and Dacian) belonged to the Baltic branch of Indo-European, or at least is closer to Baltic than any other Indo-European branch. However, this theory has not achieved the status of a general consensus among linguists. These are among many competing hypotheses regarding the classification and fate of Thracian.