Ancient Macedonian was spoken in the kingdom of Macedonia during the 1st millennium BC and belongs to the Indo-European language family. It's origins are disputed.
“The origins of the ancient Macedonian language are currently debated. It is as yet undetermined whether it was a Greek dialect which was part of or closely related to the Doric and/or Aeolic dialects, a sibling language of ancient Greek forming a Hellenic (i.e. Greco-Macedonian) supergroup, or an Indo-European language which was a close cousin to Greek and also related to Thracian and Phrygian languages. The scientific community generally agrees that, although some sources are available (e.g. Hesychius' lexicon, Pella curse tablet) there is no decisive evidence for supporting any of these hypotheses.”