The affix khac comes after the verb vad 'to speak' when priya or vaśa is the word in composition with it as an object.,
Thus प्रियं वदति = प्रियंवदः 'who speaks kindly'; वशंवदः 'who professes submission'.
Of the affix खच्, the letters ख् and च् are indicatory; ख् indicates the insertion of the augment मुम् 6.3.67, and च् shows that there is shortening of the vowel in certain cases 6.4.94.
In the case of प्रिय and वश with वद्, the affix खश् would have given the same result as the affix खच्. Making a separate affix in this sutra is for the sake of the aphorisms that follow, where this affix will produce different effects than खश्.
Vart:- The affix खच् comes after the verb गम् 'to go' when a word ending in a case-affix is in composition with it. As मितङ्गमो हस्ती 'the slow moving i. e. an elephant'; मितङ्गमा हस्तिनी 'the slow-moving i. e. a she-elephant'.
Vart:- This affix comes under similar circumstances when the word in composition with गम् is विहायस्; and the letter is then replaced by the word विह. As विहायसा गच्छति = विहङ्गमः 'a bird (that which goes through the sky)'.
Vart:- In the Vartikas above given, the affix खच् may optionally be considered as if it had an indicatory ड. The force of ड is to cause elision of the final vowel with what follows it. As विहङ्गः or विहङ्गमः 'a bird'. So also भुजङ्गमः or भुजङ्गः 'a serpent' (what goes crookedly).
Vart:- विहायस् is replaced by विह when the affix ड (III 2. 48) comes after the verb गम्; as विहङ्गः 'a bird'. Thus we have three forms: विहग, विहङ्ग, विहङ्गम ।,