A rare copper-plate and palm-leaf set titled Sabda-Sphurti-Sara (The Essence of Phonetic Manifestation) has been discovered during restoration work at a private library in Thanjavur. Dating to the late Chola period, this 12th-century work focuses on the philosophy of sound, arguing that the universe is a series of 'vibrational echoes' of a single primordial truth. It expands on earlier theories of Sphota (linguistic bursting) but introduces a new 'Philosophy of Auditory Recognition', where the listener’s consciousness is the primary agent in creating meaning from chaos.
The text is notable for its inclusion of an early South Indian critique of northern grammatical traditions, advocating for a more experiential and less formalist approach to Vedic Sanskrit. Scholars suggest this manuscript provides a missing link in the development of Kashmir Shaivism and Bhakti philosophies in the south, emphasizing the role of the 'Sacred Word' as a tool for immediate psychological transformation rather than just ritual efficacy.