सन्-यङोः

The word सन् यङोः should be construed as genitive dual and not as Locative dual. In the latter case, the meaning would be \when the affixes सन् and यङ् follow, a non-reduplicate root is reduplicated\. The difficulty would be that while the root alone would be reduplicated. the augment इट् would not, as in अटिटिषति, अशिशिषति ॥

The phrase धातोरनभ्यासस्य is understood here also. The reduplication is of the first or second syllable, according as the root has an initial consonant or vowel. Thus पच् + सन् (III. 1. 7.) पक्ष, reduplicate पिपक्षति 7.4.79. So पत् पिपतिषति, ॠ — अरिरिषति, उन्द — उन्दिदिषति ॥ So also of यङन्तः - as, पापच्यते 7.4.83, अटाट्यते, यायज्यते, अरार्यते, प्रोर्ण्णोनूयते ॥ If a root is already a reduplicated one, there is no reduplication : as जुगुप्सषते, लोलूयिषते being the Desiderative forms of जुगुप्स (already formed by svarthika सन् 3.1.5, and of लोलूय (the Intensive form of लु) ॥ See (III. I. 22).,