Question
Is Sanskrit the oldest language? Is it older than Pali?
Answer
The oldest surviving Buddhist texts in the Pali language come from the relic chamber of a Buddhist stupa at Sri Ksetra. They consist of a twenty-leaf manuscript of solid gold and a large gilded reliquary of silver. A new and exhaustive palaeographic study of these inscriptions shows that they date from the mid-fifth to mid-sixth century AD.
This link provides multiple reference to support this claim : http://dhammawheel.com/viewtopic.php?t=6033
The Rig Veda, a Sanskrit text was written around 1500 BC. Although, it is said that there was an oral tradition spreading it for a very long time. Hence, Sanskrit is older, as Sanskrit texts were written way back. This link provides the dates when the Sanskrit texts were written including Rig Veda:
https://en.wikipedia.org/wiki/Timeline_of_Hindu_texts
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