Words of more than two syllables are accented on the Penult[The Penult is the last syllable but one; the Antepenult, the last but two.] if that is long (as, amícus, monétur, contingit); otherwise on the Antepenult (as, dominus, alacris, dissociábilis).
a. When an enclitic is joined to a word, the accent falls on the syllable next before the enclitic, whether long or short: as, deaque, amáreve, tibine, itaque (and ... so), as distinguished from itaque (therefore). So (according to some) exinde, ecquando, etc.
Exceptions: 1. Certain apparent compounds of fació retain the accent of the simple verb, as, benefacit, calefacit (see §266. a.).
NOTE: These were not true compounds, but phrases.
2. In the second declension the genitive and vocative of nouns in -ius and the genitive of those in -ium retain the accent of the nominative: as, Cornélí, Vergilí, ingení (see §49. c.).
3. Certain words which have lost a final vowel retain the accent of the complete words: as, illíc for illíce, pródúc for pródúce, satin for satisne.