Onomatopoetic sound-syllables employed to identify ‘notional’ alphabets of various instruments. For example, in tabla, tirkid, dha, ta, na; in pakhawaj, dhingad, gadigan, dhin dhin; or in sitar, da da, dir, dir, etc., are so identified. These and such other ‘letters’ are obviously expected to give us some idea of the tonal colour produced by instruments under discussion.