I have heard that Malayalam is a more recent language ( 800 years old?) ... DEVELOPED by the assimilation of Tamil with Sanskrit. I know Tamil is an ancient language, and the Telegu -Kannada origin is an entirely different thread..
Dravidian appears to derive from Dramilia, which Buddhists believe to be non Aryan, and thus separate from the Indo-European languages.
Joseph (1989: IJDL 18.2:134-42) gives extensive references to the use of the term draviḍa, dramila first as the name of a people, then of a country. Sinhala BCE inscriptions cite dameḍa-, damela- denoting Tamil merchants. Early Buddhist and Jaina sources used damiḷa- to refer to a people of south India (presumably Tamil); damilaraṭṭha- was a southern non-Aryan country; dramiḷa-, dramiḍa, and draviḍa- were used as variants to designate a country in the south (Bṛhatsamhita-, Kādambarī, Daśakumāracarita-, fourth to seventh centuries CE) (1989: 134–138). It appears that damiḷa- was older than draviḍa- which could be its Sanskritization.
Therefore, it would appear that Dravidians proto language is indigenous to Indus-valley, and that the Aryan element did not pre-date the Persian invasion into India any earlier than 2000BC, thus creating the Indo-European language.
relating to or denoting a people speaking an Indo-European language who invaded northern India in the 2nd millennium BC, displacing the Dravidian and other aboriginal peoples.
There are however certain proponents which believe even Dramilian may have already been an Indo-european language, arriving in India as early as 4000bc.
The origins of the Dravidian languages, as well as their subsequent development and the period of their differentiation are unclear, partially due to the lack of comparative linguistic research into the Dravidian languages. Though some scholars have argued that the Dravidian languages may have been brought to India by migrations in the fourth or third millennium BCE
However, it is unclear whether or not Dramilian was introduced from an earlier Iranian invasion.
There is no proof for this.
And the earliest provable evidence suggests that European did not arrive in India prior to the Persian invasion of 2000BC.