([b.]) But before two consonants, before r, before vowels, and after i, atonic e does not change: as, lévāmentum ([224]), but lévāminis, of consolation; óbsessus (but óbsideō), possessed; sócietās, society, from the stem socie- (but nóvitās from the stem nove-); géneris, of the kind; ádeunt, they approach.
[104]. ([c.]) Atonic medial a, except in the cases mentioned below under (d.), (e.), and (f.), was first weakened to e and then underwent the same changes as atonic medial e ([103]): as (before single consonants), cṓnficiō, accomplish, from faciō; ī́nsiliō, jump in, from saliō ([1019]); rédditus, restored, from datus; trícipitem, three-headed, from *trícapitem (caput), Cic. O. 159; occiput, back of the head, and sinciput, jole ([478]). In compounds of iaciō ([940]), -iaciō is weakened in early Latin to -ieciō (as, conieciō, [940]), but later to -iciō (as, subiciō). This last form may be due to syncope ([111, a]) of the radical a. The spelling -iiciō (as, subiiciō) is late and faulty ([52]). It does not occur in republican inscriptions and owes its origin to a confusion of the two forms conieciō and coniciō. (On the quantity of the vowel of the prepositions in these compounds of iaciō, see [122] e); (before p, b, f, m) áccipiō, accept, and óccupō, occupy, from capiō; cóntubernālis, room-mate, from taberna; ábripiō, to snatch away, from rapiō; (before two consonants) pépercī, I have spared, from parcō; áccentus, accent, from cantus; (before r) péperī, I brought forth, from pariō.
([d.]) But an a in the preceding syllable may protect the atonic a: as, ádagiō, ádagium, proverb, but prṓdigium, miracle ([144]).
([e.]) Atonic medial a before the guttural nasal ([62]) n followed by g changed to i ([138]): as, áttingō, touch, from tangō.
([f.]) Atonic medial a before l followed by any consonant save l changed to u (both l and u being guttural, [60], [44]): as, éxsultāre, to leap up, from saltāre; but féfellī, I deceived, from fallō.
[105]. ([g.]) Atonic medial o, when followed by a single consonant, first changed to e and then underwent all further changes of medial atonic e: as, hóminis, from *homon-is ([485]); ímāginis, for *imāgonis, [226] (nominative imāgō, [485]); cúpīdinis, for *cupīdonis, [225], (nominative cupīdō, [485]); vírginis, for *virgonis (nominative virgō, [470]); ī́licō, from *in-slocō, on the spot ([169, 4]).
([h.]) Before two consonants or before guttural l ([60]) atonic medial o changed to u: as, éuntis, from *éontis (Greek ἴοντος); sēdulō, from sē dolō ([1417]). But a preceding v or u protects o ([107, c]).
([i.]) Before r, atonic medial o was retained: as, témporis, of time; except when u in the preceding syllable induced a change to u: as, fúlguris, of lightning (for the -r in the nominative singular fulgur instead of -s, see [154]).
[106.] (k.) Medial -av-, -ov-, and -iv- in posttonic syllables were weakened to u: as, dḗnuō from dḗnovō ([94]); ábluō from ablavō. The form puer, boy, arose from the older POVER in enclitic vocatives ([93, 7]) and was thence transferred to the nominative like piter in Iūpiter ([94]).