Borrowed retroflex sounds

[Guest guest]

I understood from the postings of some scholars that the retroflex sounds

(T ,TH, D, DH and N) were borrowed by Vedic (or whatever dialect AMT

people were speaking around 1000 BCE) from earlier Dravidian substrate

languages of the subcontinent. I remember reading that by 700 BCE, the

Sanskrit alphabet as it is today was ready. Here is question-There are

many words in Sanskrit where the sound of "N" follows the sound of the

semivowel "r". Examples 1) GrahaNa 2) KaraNa 3)CaraNa 4)BharaNa 5)DharaNa

6)ZaraNa 7)AavaraNa 8)HaraNa 9)PraaNa. Before the borrowing of retroflex

nasal "N", what was the sound in place of "N" in these words? Or were all

these words borrowed by Sanskrit from Dravidian? And what about the

words-1) KaNa(particle) 2)KshaNa(instance) 3)ANu (atom)4)PaNa(to

trade),5)GaNa(to count) 6)GaNeZa or GaNapati.

We know Vedic verse--GaNaanaam tvaa GaNapatim Havaamahe---etc. Was this

verse composed after borrowing "N" from Dravidian language? Sanskrit has

two words-1) Anu-this is Upasarga while 2)ANu means atom. Is the word

"ANu" from Dravidian language? I am puzzled. Could any body throw light

on this subject please? I hope I made myself clear in phrasing the

question.Thanks in advance. N.J.Joshi.