Its exact origin is debated
Morgenstierne saw a special link with Bactrian, the language of the Kushan inscriptions, and also suggested that Pashto began as a Saka dialect. Cheung (2015) argues for a mixed history: some features are shared with Bactrian, Munji and Yidgha, others with the Saka languages.
Pashto, Munji and Yidgha all turned an old d into l, as in Pashto las, ten, where Persian has dah. Wanetsi split off early and is sometimes counted as a language of its own.