Agni Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · War Astrology: Yogas, Nakshatras
युद्धजयार्णवः (योगाः नक्षत्राणि)
अआकचटतपयाः श आद्यो वर्ग ईरितः ।इईखछठथफराः षो वर्गश्च द्वितीयकः ॥ १७ ॥
In the full Agni Purana this is chapter 125, verse 17.
The first group is told: a, aa, ka, cha, Ta, ta, pa, ya and sha. The second group is i, ii, kha, chha, Tha, tha, pha, ra and Sha.
Simple meaning: The first two letter groups, nine letters each, are named here.
उऊगजडदबलाः सो वर्गश्च तृतीयकः ।
The third and fourth letter groups, nine letters each, are named here.
ओऔअंअः,ङञणना मो वर्गः पञ्चमो भवेत् ।
The fifth letter group is named here. All the groups together have forty-five letters.
बालः कुमारो युवा स्याद्वृद्धो मृत्युश्च नामतः ।
These are the names of the five life stages and of four other states.