linguistic:paraphrasing, linguistic:voice_change, structural:expansion, information:filtering, quality:corruption
The Iranian languages, also called the Iranic languages, are a branch of the Indo-Iranian languages in the Indo-European language family that are spoken natively by the Iranian peoples, predominantly in the Iranian Plateau.

The Iranian languages are grouped in three stages: Old Iranian (until 400 BCE), Middle Iranian (400 BCE – 900 CE) and New Iranian (since 900 CE). The two directly-attested Old Iranian languages are Old Persian (from the Achaemenid Empire) and Old Avestan (the language of the Avesta). Of the Middle Iranian languages, the better understood and recorded ones are Middle Persian (from the Sasanian Empire), Parthian (from the Parthian Empire), and Bactrian (from the Kushan and Hephthalite empires).