1. The old diphthong ai became the classical ae (aedílis for old aidílis), old oi became oe or ú (únus for old oinos), and old ou became ú (dúcó for old doucó).
2. In compound verbs the vowel a of the simple verb often appears as i or e, and ae similarly appears as í: -
NOTE: This change is commonly ascribed to an accentuation on the first syllable, which seems to have been the rule in Latin before the rule given above (see §12). became established. The original Indo-European accent, however, was not limited by either of these principles; it was probably a musical accent so-called, consisting in a change of pitch, and not merely in a more forcible utterance of the accented syllable.
3. Two vowels coming together are often contracted: -
4. An old s regularly became r between two vowels (rhotacism), passing first through the sound of (English) z: -
Dissimilation, the opposite kind of change, prevented in some cases the repetition of the same sound in successive syllables: -
Thus, parília for palília (from Palés); merídiés for ¥medídiés; nátúrális with suffix -ális (after r), but populáris with -áris (after l).
7. Final s was in early Latin not always pronounced: as, plénu(s) fidéí.
NOTE: Traces of this pronunciation existed in Cicero's time. He speaks of the omission of a final s before a word beginning with a consonant as ``countrified'' (subrústicum).
8. A final consonant often disappears: as, virgó for ¥virgón; lac for ¥lact; cor for ¥cord.
9. G, c, and h unite with a sollowing s to form x: as, réx for ¥régs; dux for ¥ducs; tráxí for ¥trahsí.[Really for ¥traghsí. The h of trahó represents an older palatal sound (see §19).]
10. G and h before t become c: as, réctum for ¥regtum; áctum for ¥agtum; tráctum for ¥trahtum[Really for ¥traghtum. These are cases of partial assimilation (cf. 6, above).]
11. Between m and s or m and t, a p is often developed: as, súmpsí for ¥súmsí; émptum for ¥émtum.
16. In compounds with prepositions the final consonant in the preposition was often assimilated to the following consonant, but usage varied considerably.
There is good authority for many complete or partial assimilations; as, for ad, acc-, agg-, app-, att-, instead of adc-, adg-, etc. Before a labial consonant we find com- (comb-, comp-, comm-), but con- is the form before c, d, f, g, cons. i, q, s, t, cons. v; we find conl- or coll-, conr- or corr-; có- in cónectó, cóníveó, cónítor, cónúbium. In usually changes to im- before p, b, m. Ob and sub may assimilate b to a following c, f, g, or p; before s and t the pronunciation of prepositions ending in b doubtless had p; surr-, summ-, occur for subr-, subm-. The s of dis becomes r before a vowel and is assimilated to a following f; sometimes this prefix appears as dí-. Instaed of ex we find ef- before f (also ecf-). The d of red and séd is generally lost before a consonant. The preposition is better left unchanged in most other cases.