Exactly. Dravidan language.
It was neither the spoken Tamil of today. How strong are you to say dravidian language was only Tamil?
There are only few Tamil words used in Malayalam. Malayalam has more Sanskrit words than Tamil.
And, Tamil too has n number of Sanskrit words. Thats an exchange, evolution. But saying, Malayalam as a different language did not even exist is utterly stupid as your kannadiga pride.
Malayalam existed. Tamil existed.
Malayalam borrowed some words from Tamil and many words from Sanskrit. End of discussion.
No one said it was "invented." Languages evolve through linguistic drift, just like Latin branched into Spanish and Italian. The 12th century marks when the western coastal dialect of Proto-Tamil-Malayalam formally emerged as a distinct literary language (e.g., Ramacharitam).