[169.] Initial disappearance. (1.) Initial tl changed to l: as, lātus, borne, for *tlātus from tollō ([187], [917]).
([2.]) Initial gn changed to n: as, nātus, born, for earlier GNATVS from the stem gen-, gnā ([187]); nōscō, I find out, for gnōscō, GNOSCIER ([897]); nārus, knowing, for the more frequent gnārus, nāvus, active, for gnāvus. Cf. the compounds cō-gnātus, cō-gnōscō, ī-gnārus, ī-gnāvus ([170, 6]) which preserve the g. But Gnaeus retained its G.
([3.]) Initial d when followed by consonant i (i̭), disappeared: as, Iovis, Iūpiter, for *Di̭ovis, *Di̭ūpiter. Where the i was vocalic, d was retained: as, dīus.
([4.]) Initial stl- first changed to sl and then to l: as, Old Latin stlocus, place, stlīs, law-suit (Quint. 1, 4, 16), STLOC, SLIS, classical locus, līs; also lātus, wide, for *stlātus. That a form *slocus existed is proved by īlicō ([698], [703]) from *in-slocō, on the spot ([170, 2]).
[170.] Medial Disappearance. (1.) c, g, p, and b disappear before s followed by an unvoiced consonant: as, sescentī, six hundred, for *sexcentī from sex; illūstris, resplendent, for *illūcstris from lūceō; discō, I learn, from *dicscō for *di-tc-scō ([834]), a reduplicated present from the root dec- (cf. decet) like gignō (from the root gen-), and sīdō (for *si-sd-ō, [170, 2], from the root sed-, [829]). Sometimes prepositions follow this rule: as, asportō, I carry off, for *absportō, suscipiō, I undertake, for *subscipiō (subs formed from sub like abs from ab; sub-cipiō gives succipiō); occasionally also ecferō, for exferō, I carry out. But more frequently prepositional compounds remain unchanged: as, obscūrus, dark; abscēdō, I withdraw. In some words the lost consonant has been restored by analogy: as, sextus, sixth, for *sestus (cf. Sēstius) after sex; textor, weaver, for *testor after texō.
([2.]) s before voiced consonants was voiced ([75]) and is dropped. If a consonant precedes the s this is dropped also. In either case the preceding vowel is lengthened. Voiced s alone is dropped: as, prīmus, first, for *prīs-mus (cf. prīs-cus); cānus, gray, for *casnus (cf. cas-cus); adverb pōne, behind, for *posne (cf. pos, [1410]); dīlābī, glide apart, for *dislābi; īdem, the same, for ISDEM ([678]); iūdex, judge, for iūsdex; trēdecim, thirteen, for *trēsdecim. And with subsequent shortening of the final syllable ([130, 3]) abin, goest thou? for abisn(e); viden, seest thou? for vidēsn(e). Voiced s with the preceding consonant is dropped: as, trādūcō, I lead across, trānō, I swim across, for trānsdūcō, trānsnō; but in these prepositional compounds the -ns was often retained: as, trānsmittō, I send across; sēnī, six each, for *secsnī; sēmēnstris, every six months, for secsmēnstris; sēvirī, the Board of Six, for secsvirī; āla, wing, for *acsla (cf. ax-illa, Cic. O. 153); māvolō ([779]) for magsvolō from magisvolō, [396]; tōles (plural), goiter, for *tōnsles (cf. tōnsillae, tonsils); pīlum, pestle, for *pīnslum from pīnsere, crush; two consonants and voiced s are dropped in scāla, stair, for *scand-sla (cf. scandō).
([3.]) c falls away when it stands between a liquid and t, s, m, or n: as, ultus, avenged, for *ulctus from ulc-iscor ([980]); mulsī for *mulcsī from both mulgeō, I milk, and mulceō, I stroke; similarly other stems in -c and -g ([1000], [1014]); quernus, oaken, for *quercnus from quercus; tortus, turned, for *torctus from torqueō (for the change of qu to c, see [158]); for fortis, brave, forctis is found in old Latin.
([4.]) c drops out when it stands between n and t: as, quīntus, fifth, for older quīnctus ([2412]), from quīnque (for the change of qu to c, see [158]; for the long ī in quīnque, see [122], b). But verbs having stems in -nc or -ng retain the c in their past participles: as, vīnctus, bound, from vincīre ([1014]); iūnctus, joined, from iungere ([954]). In pāstus ([965]) c has dropped out between s and t.
([5.]) The group -ncn- was simplified to simple -n-, and the preceding vowel was lengthened: as, quīnī, five each, for *quīnc-nī ([317]); cō-nīveō, wink and blink, for con-cnīveō.
([6.]) n before gn was dropped and the preceding vowel lengthened: as, ī-gnōscō, I forgive, for *in-gnōscō, cō-gnōscō, I know, for *con-gnōscō. In this manner ([170, 5; 6]) arises a form cō- by the side of con- ([122, e]): as, cō-nectō, cō-nubium, cō-ligātus (Gell. 2, 17, 8).