lingual sibilant or semivowels or vowels—that is to say, by ष् ṣ, र् r, or ऋ ṛ or ॠ ṝ—: and this, not only if the altering letter stands immediately before the nasal, but at whatever distance from the latter it may be found: unless, indeed, there intervene (a consonant moving the front of the tongue: namely) a palatal (except य् y), a lingual, or a dental.
a. We may thus figure to ourselves the rationale of the process: in the marked proclivity of the language toward lingual utterance, especially of the nasal, the tip of the tongue, when once reverted into the loose lingual position by the utterance of a non-contact lingual element, tends to hang there and make its next nasal contact in that position; and does so, unless the proclivity is satisfied by the utterance of a lingual mute, or the organ is thrown out of adjustment by the utterance of an element which causes it to assume a different posture. This is not the case with the gutturals or labials, which do not move the front part of the tongue (and, as the influence of k on following s shows, the guttural position favors the succession of a lingual): and the y is too weakly palatal to interfere with the alteration (as its next relative, the i-vowel, itself lingualizes a s).
b. This is a rule of constant application; and (as was pointed out above, 46) the great majority of occurrences of ṇ in the language are a result of it.
190. The rule has force especially—
a. When suffixes, of influence or derivation, are added to roots or stems containing one of the altering sounds; thus, rudréṇa, rudrā́ṇām, vā́riṇe, vā́riṇī, vā́rīṇi, dātṝ́ṇi, hárāṇi, dvéṣāṇi, krīṇā́mi, çṛṇóti, kṣubhāṇá, ghṛṇá, kárṇa, vṛkṇá, rugṇá, dráviṇa, iṣáṇi, purāṇá, rékṇas, cákṣaṇa, cíkīrṣamāṇa, kṛ́pamāṇa.
b. When the final n of a root or stem comes to be followed, in inflection or derivation, by such sounds as allow it to feel the effect of a preceding altering cause: thus, from √ran, ráṇanti, ráṇyati, rāraṇa, arāṇiṣus; from brahman, bráhmaṇā, bráhmāṇi, brāhmaṇá, brahmaṇyà, bráhmaṇvant.
c. The form piṇak (RV.: 2d and 3d sing. impf.), from √piṣ, is wholly anomalous.
191. This rule (like that for the change of s to ṣ) applies strictly and especially when the nasal and the cause of its alteration both lie within the limits of the same integral word; but (also like the other) it is extended, within certain limits, to compound words—and even, in the Veda, to contiguous words in the sentence.