The affix kyac is optionally employed, in the sense of wishing after a word ending in a case-affix expressing the object wished as connected with the wisher itself.,
This forms the Denominative verbs, i.e., verbs derived from nominal bases. As, पुत्र 'son', पुत्रीयति 'he wishes for a son of his own' (पुत्र + क्यच् = पुत्री + य = पुत्रीय) 2.4.71, 7.4.33.
Why do we use the word सुप् ? The affix should not come after a whole sentence, but only after the particular word ending in the case-affix. Thus in महान्तं पुत्रमिच्छति, the affix comes only after पुत्रम् and not महान्तं पुत्रं.
Why do we say atmanah ? Observe राज्ञः पुत्रमिच्छति 'he wishes a son for the king'. Here there is no affixing as the wishing is for another and not for one's own self.
The क in क्यच् is for the sake of classing kyach, kyan and kyash in one common group by simply using the word क्य, as in sutra तः क्ये 1.4.15; while च् distinguishes kyach from kyan &c., and is not for the sake of accent, the affix will be udatta by 3.1.3.
Vart:- In affixing kyach, prohibition must be stated of pronouns in म् and of Indeclinables. Thus in इदमिच्छति, उच्चैरिच्छति, there is no affixing.
Vart:- In the Vedas, the affix is added even when the wish is with regard to another. As मा त्वा वृका अघायवो विदन्. Here अघायु (pl. अघायवः) is formed by kyach, अ being added by 3.2.170, and आ is added by 7.4.37. See Rig Veda (I. 120.7; 27.3) &c.,