Ancient Macedonian was the language or dialect spoken by the ancient Macedonians during the 1st millennium BC. It was either an ancient Greek dialect—part of Northwest Greek or Aeolic Greek—or a distinct Indo-European language, related to Greek and part of the Hellenic branch. Spoken originally in the kingdom of Macedon, it gradually fell out of use during the 4th century BC, marginalized by the use of Attic Greek by the Macedonian aristocracy, the Ancient Greek dialect that became the basis of Koine Greek, the lingua franca of the Hellenistic period. It became extinct during either the Hellenistic or Roman imperial period, and was entirely replaced by Koine Greek.
While the bulk of surviving public and private inscriptions found in ancient Macedonia were written in Attic Greek (and later in Koine Greek), fragmentary documentation of a vernacular local Macedonian variety comes from onomastic evidence, ancient glossaries, and recent epigraphic discoveries in the Greek region of Macedonia, such as the curse tablets from Pella and Pydna.