Panini’s Astadhyayi is a monumental work in the sutra format (short aphorisms) that establishes the grammar of ancient Sanskrit as a language. At the same time, the text also presents a general model for language description, that goes beyond Sanskrit as a specific language instance. This is the fourth course in a sequence of four courses on Vyakarana (grammar) based on Panini’s Astadhyayi. The formalism of grammar developed by Panini has its foundation in the philosophy of language in the Indian tradition elucidated by Vaydi. After Panini, Bhartihari explained this comprehensively in his compendium named Vikramaditya, which elucidates the universal philosophy of language, and is considered as a pathway to liberation in the Vyakarana tradition.