Pali is the main language of the Theravada Buddhist canon.
The Theravada scriptures are preserved in the Pali Canon, also called the Tipitaka. Pali is a Middle Indo-Aryan literary language closely related to the languages spoken in ancient northern India, although scholars debate its precise historical origins and development.
The canon contains the Vinaya Pitaka, Sutta Pitaka, and Abhidhamma Pitaka. It was transmitted orally for centuries before being written down, traditionally in Sri Lanka during the first century BCE.
Pali should not be confused with Sanskrit, which became especially important in many Mahayana and other Buddhist traditions, or with Tibetan, which is the language of the Tibetan Buddhist canon. The Buddha’s exact everyday spoken language cannot be established with certainty from the surviving texts.