The question I always wondered was whether the Dravidian speakers had any clannish identity of their own. It is unknown what the people of Indus valley called themselves. Some of the Sumerian and Akkadian texts talk about "Meluhha" which has been identified with Indus valley. But that is still controversial. Also, the identity looks like given one by non Indus valley people just like the name India. More importantly we do not know if Indus valley people spoke Dravidian languages or not. My inclination is the people of Indus valley spoke languages belonging to different families. Therefore, I want to investigate if they had any kind of national identity.
The birth of a nation with consonants:
The one thing(may be two) that caught my eye was consonants "t" and "l" in Telugu, Tulu and Tamil. So let us start constructing the original national identity.
Let me call these people "Tala". The "l" could have been pronounced as retroflex approximant(zh) or alveolar trill(r). Both these are still alive in Tamil and Malayalam and was alive till 12th century in Kannada. In Kannada, retroflex approximant has turned into "La" and alveolar trill has turned into "ra". This gives us the clue for the various sound changes.
Let me group the people who I think were part of Indus valley.
Group 1 : Burushos, Brahui
Group 2 : Tulu , Telugu
Group 3 : Kannada, Tamil, Gonda
Group 4: Kodava
Group 5: Toda
Case 1: Group 2 still shows the oldest unchanged identity. First Group 1 and Group 2 connection.
1. Tulu -> Burusho
Tulu + AN (male or people) -> TuluvAN (vakArAgama sandhi) -> TuruvAsha -> Burusho
Note:I believe "sho" or "sha" basically meant people.
Rule 1: In North, the sound changes are mostly t->b and alveolar trill to "ra".
2. Tulu -> Brahui or Brohi
By rule 1 : Tuluvan -> Buruvan -> Buruva -> Bruva -> Brovi -> Brohi
Tuluvan -> Buruvan -> Buruvash(s) -> Buruvah(When you cross Sindh s changes to h) -> Bruha -> Brohi
Let's discuss about Group 3. This is an interesting group. Here etymology of Kannada or Karnataka has been traced to karu + nAdu meaning elevated land. That sounds like given identity and not the self one. I am suspicious of such imaginative identities. In my opinion, Group3 follow the similar pattern.
If you observe Tamil changes to Damida in Prakrit. Therefore, La-Da change is possible. However, one more interesting thing happened here. The "anusvara" came in between "ta" and "la". This anusvara based on succeeding consonant can take "um" or "un" form(though both pronunciations are wrong, but we have to understand people were illiterate).
Also, in the regions of Central India and Karnataka, there were additional changes;
ta -> ka
Rule 2: In the region of Karnataka, tala should change to kada.
tala -> ta(m)la -> tamil
Group 4 is late migrants to the region of Karnataka as a result they do not show insertion of anusvara.
By Rule 2:
Group 5 is probably late migrants to Nilgiri hills in Tamil Nadu. They only show la-> da changes.
tala -> tada -> toda
What is Meluhha's original form?
By rule 1:
tuluvan-> buruvan-> buruvash(s)-> buruvahh(west of Sindh s->h) ->muluhha(retroflex approximant making a come back in the place of alveolar trill)-> meluhha (b->m change could be unique to Sumerians and Akkadians)
Note: I have already discussed that the original mother was "abba" or "appa" as it's still in Tulu. You can see, b->m transition is possible in every language just as abba became amma.
Now, the earliest people of Vedic India, Kuru and Puru are within the range of sound change of Tulu.
I think I need another long break.