Reconstruction:Proto-Vietic/b-laŋ
Proto-Vietic
Etymology
This Viet-Muong etymon is often compared with Austronesian *bulaN; however, in spite of Ferlus' reconstruction, none of the modern reflexes indicate that the labial element was voiced (the tones in the languages belong to upper register, signifying a voiceless presyllable), and they uniformly have final *-ŋ, which does not match with either Austronesian (PA with lateral coda, PMP and its reflexes with alveolar nasal) nor Kra-Dai forms (with alveolar nasal coda).
On the other hand, Chut [Mày] pula̤n² ~ pala̤n² (Babaev & Samarina, 2018) (as well as its close cognate in Rục) is a more obvious loan, with lower register tone indicating earlier voiced presyllable, and a -n coda.
Note that this Viet-Muong etymon and Chứt forms can not be immediate cognates (if they are even related at all); beside the aforementioned differences, the vowel of the Chứt forms is long ((Babaev & Samarina, 2018) indicates vowel length in Mày as ă-a, instead of a-aː), while the Viet-Muong forms have short vowel.