214. These sounds show in some situations a reversion (43) to the original gutturals from which they are derived. The treatment of j and h, also, is different, according as they represent the one or the other of two different degrees of alteration from their originals.
215. The palatals and h are the least stable of alphabetic sounds, undergoing, in virtue of their derivative character, alteration in many cases where other similar sounds are retained.
216. Thus, in derivation, even before vowels, semivowels; and nasals, reversion to guttural form is by no means rare. The cases are the following:
a. Before a of suffix a, final c becomes k in an̄ká, çvan̄ka, arká, pāká, vāká, çúka, parka, marká, vṛ́ka, prátīka etc., reka, séka, moka, roká, çóka, toká, mroká, vraská;—final j becomes g in tyāgá, bhága, bhāgá, yāga, an̄ga, bhan̄gá, san̄ga, svan̄ga, ṛñga, tun̄ga, yun̄ga, varga, mārga, mṛgá, varga, sarga, nega, vega, bhóga, yugá, yóga, loga, róga;—final h becomes gh in aghá, maghá, arghá, dīrghá (and drā́ghīyas, drā́ghiṣṭa), degha, meghá, ogha, dógha, drógha, mógha; and in dúghāna and méghamāna. In neka (√nij) we have further an anomalous substitution of a surd for the final sonant of the root.
b. In another series of derivatives with a, the altered sound appears: examples are ajá, yāja, çucá, çoca, vrajá, vevijá, yuja, ūrjā́, dóha.
c. Before the suffixes as and ana, the guttural only rarely appears: namely, in án̄kas, ókas, rókas, çókas, bhárgas, and in rogana; also in ābhogáya.
d. Before an i-vowel, the altered sound appears (except in ābhogí, ógīyaṅs, tigitá, mokī́, sphigī́): thus, ājí, tují, rúci, çácī, vívici, rociṣṇú.
e. Before u, the guttural reappears, as a rule (the cases are few): thus, án̄ku, van̄kú, rekú, bhṛ́gu, mā́rguka, raghú (and rághīyaṅs).
f. Before n, the examples of reversion are few, except of j (becoming g) before the participial ending na (957 c): thus, rékṇas, vagnú (with the final also made sonant); and participles bhagná, rugṇá, etc.; and apparently pṛgṇa from √pṛc.
g. Before m (of ma, man, mant, min), the guttural generally appears: thus, rukmá, tigmá, yugma, ṛ́gma (with sonant change); takmán, vákman, sákman, yugmán; rúkmant; ṛgmín and vāgmín (with sonant change):—but ájman, ojmán, bhujmán.
h. Before y, the altered sound is used: thus, pacya, yajya, yajyu, yujya, bhujyu. Such cases as bhogya, yogya, negya, okya are doubtless secondary derivatives from bhoga etc.