8.4.47
अनचि च
Operational rule vidhi
The यर् letter that follows an अच् letter but is not followed by an अच् letter is optionally duplicated.
Word by word (padaccheda)
Right context अनचि saptamī · ekavacanaIndeclinable च avyaya
- 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").
- 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
अनचि च
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
When a vowel does not follow, there is reduplication of यर् (all consonants except ह) after a vowel.
The words अचः and यरः are understood here.
Thus दधि + अत्र = दध्य् + अत्र 6.1.77 = दध्ध्य् + अत्र दद्ध् + अत्र 8.4.53 = दद्ध्यत्र, so also मद्ध्वत्र ॥
Why do we say अचः "after a vowel ?" Observe स्मितम्, स्मातम् ॥
Vart:- यणो मयो द्वे भवतः ॥ This Vartika may be interpreted in two ways. First taking यणः as ablative and मयः as genitive. "The letters of the pratyahara मय् are reduplicated after यण् letters." उल्क्का, वाल्मीकः ॥ Secondly taking यणः as genitive, and मयः as ablative. "The letters यण् are reduplicated after मय् letters". As दध्ययत्र, मध्व्वत्र ॥
Vart.- शरः खयो द्वे भवतः ॥ This is also similarly explained in two ways. Ist "There is reduplication of खय् letters, after a sibilant for शर् letters". as स्थ्थाल, स्थ्थात. Secondly. There is reduplication of a sibilant (शर् letters), after खय् letters, ss, वत्स्सरः, अप्स्सराः ॥
Vart:- अवसाने च यरो द्वे भवतः ॥ There is reduplication of यर् when a Pause ensues. As वाक्क्, त्वक्क्, षट्ट्, तत्त् &c.
These reduplications are curiosities, rather than practicalities.
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.