Paisaci, also known as Paisachi, or Paishachi, is an extinct language of classical India, mentioned as a medium of debate and literary expression in various Theravada Buddhist sources, and in Prakrit and Sanskrit grammars of antiquity. It is not known to what extent this was a vernacular or an artificial literary language, comparable to Pāli.
The Sanskrit etymology of the name of the language (suggesting that it means "spoken by demons") is deemed by modern scholars to be either jocular or simply false. As with most languages, the name seems to be devolved from a toponym associated with the origin or homeland of the language. In works of Sanskrit poetics such as Daṇḍin's Kavyadarsha, it is also known by the name of Bhutabhasha.
There are no extant works in this language today, and the only work attributed to be in Paisaci is the Brihat-katha (The Large Story), a large collection of stories written in the 5th century BC. It is known of through its adaptation in Sanskrit as the Katha-Saritsagara in the 11th century by Somadeva. One of the famous series of stories in this work is the Vikram and Vetaal series. Talking of its existence, Pollock writes[1]:92:
Linguists have identified this as everything from an eastern Middle-Indic dialect close to Pali to a Munda language of inhabitants of the Vindhya Mountains […] In fact there is little reason to bother to choose […] Paishachi is the joker in the deck of South Asian discourses on language, having an exclusively legendary status, since it is associated with a single lost text, the Bṛhatkathā (The Great Tale), which seems to have existed less as an actual text than as a conceptual category signifying the Volksgeist, the Great Repository of Folk Narratives […] In any event, aside from this legendary work (which "survives" only in one Jain Maharashtri and several Sanskrit embodiments), Paishachi is irrelevant to the actual literary history of South Asia.
Historian Vishwanath Kashinath Rajwade claims that some of the old works like Krista Purana, Krishnadas Shama's Mahabharat composed in Konkani language reveal that modern Konkani might be a successor of Paishachi.[2]