The Greater Siangic grouping was proposed by Roger Blench (2014), based on exclusively shared lexical items that had been noted by Modi (2013).
Various lexical items exclusively shared by Milang, Koro, Taraon, and Idu have also been noted by Modi (2013).
[1] Modi (2013) suggests that Taraon could be closer to Milang than Idu is.
Blench (2014) lists the following languages in Greater Siangic.
Modi (2013: 20-22)[1] notes the following sound correspondences among Milang, Taraon, Idu, and Proto-Tani.