The Upanishads, Part 2 (SBE15), by Max Müller, [1879], at sacred-texts.com

p. 46

SECOND ANUVÂKA.

1. Om 1! Let us explain Sîkshâ, the doctrine of pronunciation, viz. letter, accent, quantity, effort (in the formation of letters), modulation, and union of letters (sandhi). This is the lecture on Sîkshâ.

Footnotes

46:1 Cf. Rig-veda-prâtisâkhya, ed. M. M., p. iv seq.