Question

Which is the earliest composition of sanskrit language?

Answer 1

If you are referring to Vedic Sanskrit,then it is rigveda.
But if you are referring to classical Sanskrit then it is ramayana.

Answer 2

There are four types of vedas- 1. Rig ved, 2. Sama ved 3. Yajur ved 4. Atharv ved. " Rig Ved" is considered as the earliest composition of sanskrit language.