I am currently reading about Kālidāsa, perhaps the greatest poet of all times, and about the language he used, Sanskrit.
Kālidāsa (कालिदास) was a Sanskrit poet and dramatist, his title Kavikulaguru (Preceptor of All Poets) bearing testimony to his stature. His name means, literally, "Kali's servant".
Sanskrit has been called the language of the Gods; the most perfect, the most sublime. It is definitely the most ancient one (Vedic Sanskrit dates back at least to the Mahabharata's age -- about 8000 b.C.).
Following is a striking excerpt about Sanskrit, by Sri Aurobindo.