It is a fascinating look at the diverse weaving traditions of Southwestern China in particular and Asia in general

Additionally it also attempts to reconstruct its history via what is basically the comparative method and how it intersects with the language families of the area

On the other hand, if you show a reconstructed Middle Chinese reading you mid start a brawl amongst the Sinologists 🤣

The existence of evidently related roots རིས ris and རི་མོ ri-mo, both “painting” also suggest the initial b- is of secondary origin

The former evidently zero nominalised from the ‘imperative’ stem (likely original a stative passive) རིས ris and the latter from the root plus the nominal suffix -མོ -mo

This seems to suggest that in Old Tibetan, the underlying root is √རི √ri with the epenthesis of <d> when adding the prefix ɣ- as seen in the root √རལ √ral “to tear” with stems འདྲལ ɣdral (v1) and རལ ral (v2)

However, this is evidently an innovation as in Old Tibetan, instead of Classical འབྲེལ ɣbris and བྲེལ bris, we instead find the verbs forms འདྲིས ɣdris and རིས ris

In Classical Tibetan sources, this verb is reported with the stems འབྲེལ, བྲེལ, བྲེ and བྲེལ (ɣbris, bris, bri, bris), fitting into Coblin’s Paradigm I with the loss of preinitial b- before a labial consonant