RK ji
What you mean by language ???
Same question is put to other members who say Haryanvi is not a language.
If someone says that it is a boli of Hindi than he simply does not know that there was no Hindi just few centuries earlier but languages Brij ,Deswali,Bagari were even than spoken by same people.
Sanskrit was never used as a language of communication than How can it be considered a language ?
Now take case of Script, Devanagari itself came out of Sarda which came out of Gupta than Brahmi etc....etc..This is a continuous process.
Lastly came question of some written material as we know a lot was destroyed in Muslim invasion and later this invasion lead to development of Hindi and Urdu ,but we have still a lot written in Brij ,Marwari and other Languages /dialects of this earlier Haryana Desh .
Finally as per a common Haryanvi villager Dada Lakhmi wrote on virtually every thing that exist in this world .