प्रपरापसमन्ववनिर्दुरभि-
व्यधिसूदतिनिप्रतिपर्यपयः ।
उप आङिति विंशतिरेष सखे
उपसर्गविधिः कथितः कविना ॥
pra-parāpa-sam-anv-ava-nir-dur-abhi-
vy-adhi-sūd-ati-ni-prati-pary-apayaḥ |
upa āṅ iti viṁśatir eṣa sakhe
upasarga-vidhiḥ kathitaḥ kavinā ||
(Unknown source; cited in Hari-nāmāmṛta-vyākaraṇa-vṛtti: 406)
“The twenty—pra, parā, apa, sam, anu, ava, nir, dur, abhi, vi, adhi, su, ud, ati, ni, prati, pari, api, upa, and ā[ṅ]—[are the prādis]. O friend, this [i.e., this rule that the prādis are combined with dhātus and applied as a prefix (as per Hnv: 406)] is known by the wise as the rule of the upasarga.”
Commentary
Upasargas, known as the prādis, are avyayas because the sv-ādis undergo mahāhāra after them (as per Hnv: 362). Among the avyāyas, upasargas are classified as dyotakas (rather than vācakas) because they suggest, that is, bring out, the meaning of a dhātu to which they are affixed rather than express meaning directly. Other lists of upasargas sometimes include two additional ones, nis [which is considered here equal to nir] and dus [which is considered here equal to dur].