8.4.45
यरोऽनुनासिकेऽनुनासिको वा
Operational rule vidhi
A यर् letter occurring at end of a पद is optionally converted to an अनुनासिक when it is followed by an अनुनासिक.
Word by word (padaccheda)
Target ṣaṣṭhī · ekavacanaRight context saptamī · ekavacanaSubstitute / term prathamā · ekavacanaIndeclinable वा avyaya
- Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
- Right context Saptamī (7th case): "when X follows", the operation applies to what precedes (1.1.66 तस्मिन्निति निर्दिष्टे पूर्वस्य). Also a condition or domain ("in the sense of").
- Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.
- Indeclinable An avyaya such as च "and", वा "optionally", न "not".
Dotted words are technical terms, dashed ones pratyāhāras (names for classes of sounds or affixes). Hover or tap one to see its card.
Full reading
वा
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
→ / optional
Replace yaraḥ with anunāsikaḥ when anunāsike follows, optionally. Inherited words (anuvṛtti) may add further conditions.
Commentary
In the room of a यर् letter (every consonant except ह final) in a पद , when Nasal follows, there is optionally a Nasal substitute.
The word पदान्त is understood here. Thus वाक् + नयति = वाग्नयति or वाङ्नयति, अग्निचिद्नयति or अग्निचिन्नयति, त्रिष्टुब्नयति or त्रिष्टुम्ननयति, श्वलिण्नयति or श्वलिड्नयति ॥
Why do we say 'final in a Pada'? Observe, वेद् + मि = वेद्मि ॥ Here there is no option. So also क्षुभ्नाति ॥
Vart:- When it is a pratyaya or affix that follows, the nasalisation is obligatory in the secular language. Thus वाक् + मात्रम् = वाङ्मात्रम्, कियन्मात्रम् ॥ It is, however, only before the affixes मय and मात्र that the change is obligatory, and not before every affix beginning with a nasal.
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.