Mustafa is a multilingual actor, and he speaks both Dari and Pashtu languages. Dari is one of the two formal languages in Afghanistan, and almost 90 percent of Afghans speaks it.
Dari language has a lot in common with Farsi language (spoken in Iran) in written form, but it is very different in terms of accent and speaking form. Dari speakers can speak in Farsi (Persian) accent almost perfectly; however the Iranians will have a hard time picking up the Dari accent.