Sphota -Patanjali

                     Patanjali also defines an early notion of sphota, which would be elaborated considerably by later Sanskrit linguists like Bhartrihari. In Patanjali, a sphoTa (from sphuT, burst) is the invariant quality of speech. The noisy element (dhvani, audible part) can be long or short, but the sphoTa remains unaffected by individual speaker differences. Thus, a single letter or 'sound' (varNa) such as k, p or a is an abstraction, distinct from variants produced in actual enunciation. This concept has been linked to the modern notion of phoneme, the minimum distinction that defines semantically distinct sounds. Thus a phoneme is an abstraction for a range of sounds. However, in later writings, especially in Bhartrihari (6th c. AD), the notion of sphoTa changes to become more of a mental state, preceding the actual utterance, akin to the lemma.

                       Patañjali's writings also elaborate some principles of morphology (prakriyā). In the context of elaborating on Pāṇini's aphorisms, he also discusses Kātyāyana's commentary, which are also aphoristic and sūtra-like; in the later tradition, these were transmitted as embedded in Patañjali's discussion. In general, he defends many positions of Pāṇini which were interpreted somewhat differently in Katyayana.