'bo*' is pretty common for cows in european languages - they are the genus 'bos' after all (see: english 'bovine'). As for the Vietnamese roots, I thought it m

'bo*' is pretty common for cows in european languages - they are the genus 'bos' after all (see: english 'bovine'). As for the Vietnamese roots, I thought it might have been a French loanword but it looks like it came from a proto-vietnamese language: https://en.wiktionary.org/wiki/b%C3%B2#Etymology_1 https://en.wiktionary.org/wiki/b%C3%B2#Etymology_1