Phonetics is the study of linguistic sound in its physical aspects, articulatory and auditory/acoustic. Already by an early period, the phonetic analysis of Sanskrit had reached an advanced stage in India. Śikṣā, the name of the phonetic and phonological tradition, literally means ‘instruction’, possibly reflecting both its importance as the first stage of linguistic education, and its priority in the historical development of linguistic analysis.

Surviving Śikṣā texts, which describe in detail the articulation of all Sanskrit sounds, are late, but must reflect a very early tradition, and evidence a sophisticated articulatory analysis. Famously, the Indian tradition accurately understood the articulatory process of voicing – i.e. vibration of the vocal chords – which was not understood in the Western tradition until the nineteenth century.