Pāṇini sūtras

Of that whose first syllable begins with a vowel, there are two in the room of the second portion containing a single vowel.

German Und: “lautet die erste Silbe aber vocalisch an, so werden für die zweite Silbe zwei gesetzt, d. i. so wird die zweite Silbe reduplicirt”. (2)

1. a+c+ādeḥअ+च्+आदेः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   aअ	aअ	aअ	akāraअकार	aअ
   cच्	cच्	cच्	CC	cच्
   āआ	ādiआदि	ādeḥआदेः	first syllable	ādआद् + plus eḥएः

2. dvitīyasyaद्वितीयस्य

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   dद्	dvitīyaद्वितीय	dvitīyasyaद्वितीयस्य	second	dvitīyद्वितीय् + plus asyaअस्य

Anuvṛtti

1. prathamasyaप्रथमस्य 6·1·1

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   pप्	prathamaप्रथम	prathamasyaप्रथमस्य	first	prathamप्रथम् + plus asyaअस्य