In those languages are, (1) Boorishki or Khajuna, the language of the Boorish or Yeshkuns, which is spoken in Hunza, Nager, and Yassin, (2) Shina, the language of the Shins which is spoken in the Gilgit Valley, (3) Khowar, the language of Chitral.
Source: wiktionary
Few people in Rowshan regularly read Khowar works, however, and their attitudes towards the value of written Khowar are ambivalent.
Source: wiktionary
Morgenstierne 1936 is a foundational article for Khowar etymological studies. It discusses four layers of historical accretion of Iranian lexical elements in Khowar: words from (a) unidentified Ir sources, (b) Pamir languages, mainly Wakhi, (c) Middle Ir. languages, and (4) numerous words from New Persia.
Source: wiktionary