tấy

Etymology
See.

In spite of a phonological discrepancy, rái and tấy are both regular reflexes of the Proto-Vietic word in terms of dialectal development, wih most Vietnamese dialects spirantized medial *-s- to ‹r› while the North Central dialects kept the *-s- (that later regularly shifted to ‹t›) unaffected by the presyllable *p-. For the ‹ay›-‹ây› (< *eː) correspondence, compare North Central vs. standard written,  vs. ,  vs..