The Tangshewi [tnf] entry carries minimal information but is listed as an unclassified Iranian languages and is located on the map in the NE Afghani Badakhshan. The name signifies it is spoken at least in Darrah-e Tang Shew. All other sources, e.g., Leila Dodykhudoeva 1997 , Simone Beck 2013 :239 place Roshani (of the Shughni-Roshani group [sgh], see Džoy I. Edelman and Leila R. Dodykhudoeva 2009 , Džoy I. Edelman and Leila R. Dodykhudoeva 2009 ) here, and Georg Morgenstierne 1928 has Shewa as a Shugni group village, though not impossibly a Tajik dialect could also be spoken there. In either case, the Tangshewi [tnf] entry arguably duplicates a language already included in E16, either a Tajik dialect such as Darwazi [drw] or a Shughni Pamir variety [sgh]. See also: Shughni [sgh], Darwazi [drw].
Retired in ISO 639-3: merge with [prs] Dari
Excerpt from change request document:
Lexical similiarity of Dari and Tangshewi is between 86% and 90%. Comprehension testing of Eastern Farsi (Dari) showed that Dari is highly intelligible for the Tangshewi people. The Tangshewi call the valley they live in Tangshew valley but not their speech variety. No one ever mentioned a language called Tangshewi as his mother tongue. The Tangshewi themselves explain that they speak Dari, acknowledging that their dialect is slightly different.