Malayali Classification

I think Malayalis can be broadly classified into two categories based on their pronunciation. Majority use voiced labiodental fricative (v) instead of voiced bilabial plosive (b). Also, majority use retroflex approximant (zh) instead of palatal approximant (y). Considering the different paths trodden by these two groups, the former can be labelled as 'vazhi' Malayalis and the latter 'bayi' Malayalis. Or 'vazhi's and 'bayi's.