([a.]) Nouns; G. eri, boni, preti. D. cani, ero, malo. L. domi, heri. Ab. levi, manu, domo, bona, fide. Plural: N. fores, viri. D., Ab. bonis. Ac. foris, viros, bonas. (b.) Verbs: eo, volo, ago; ero, dabo; vides; loces; voles; dedi, dedin; roga, veni; later poets sometimes retain cave, vale, and vide. The vowel may also be shortened when -n ([1503]) is added and s is dropped before -n ([170, 2]): rogan, abin; viden is also retained by later poets.
([2.]) In a few pyrrhic words (⏑ ⏑) in -i, which were originally iambic (⏑ –), the poets in all periods retained final -ī at pleasure: these are,
mihī̆, tibī̆, sibī̆; ibī̆, ubī̆; also alicubī̆. The i of bi is always short in nēcubi and sīcubi, and usually in ubinam, ubivīs, and ubicumque; ibidem is used by the dramatists, ibīdem in hexameter. ubīque has always ī.
[130]. The following instances show that this law operated in prose speech also:
([1.]) In iambic words of the ā- declension ([432]) the final -ā of the nominative singular was shortened; hence *equā became equa, mare. From these iambic words short final -a spread so that all stems in -ā- shorten the final ā of the nom. sg. ([434]).
([2.]) The final -a in the nominative plural of neuter nouns of the o- declension ([446]), which appears in trīgintā, thirty, was likewise shortened, first in iambic words like iuga, yokes, bona, goods, then everywhere ([461]).
([3.]) This law explains the short final vowel in homo ([2442]) by the side of sermō ([2437, c]) and similar cases, like the adverbs modo, cito ([2442]), bene, male ([2440]). In the same way arose the short final o of the first person in conjugation ([2443]): as, volo, dabo, dīxero by the side of scrībō; so also viden for vidēn ([129, 1]; [170, 2]).
([4.]) Of imperatives only puta, used adverbially ([2438, c]), ave, have ([805]; Quint. i, 6, 21; but Martial scans havē) as a salutation and cave, used as an auxiliary ([1711]), show the short final vowel in classical Latin. Elsewhere the long vowel has been restored, as amā, monē ([845]).
([5.]) According to this rule calēfaciō, malēdīcō changed to calefaciō, maledīcō.
[131]. A long final vowel is shortened when an enclitic is added to the word: as siquidem from sī; quoque from quō.