I was going through the BBC article on the origin of the word 'king'.
It appears both terms are of Indo-European origin. So, probably assimilated IE speakers in Dravidian lands brought with them the Proto-IE idea of a favoured son.
babu
pilla
The Anglo-Saxon "cyning" from cyn or kin, and -ing meaning "son of" evokes images of long-gone tribes choosing as leader a favoured son who is mystically representative of their common identity.I suppose somewhat similar idea is behind pan-India term 'babu' and Dravidian term 'pilla/pillai' which were the titles of high officials ( but pilla is now mostly associated with certain castes in Tamil and Malayalam regions). However, baba denotes affectionate term for son and pilla for child in general in Dravidian lands.
It appears both terms are of Indo-European origin. So, probably assimilated IE speakers in Dravidian lands brought with them the Proto-IE idea of a favoured son.
babu
pilla