Allen and Greenough's New Latin Grammar, section 629

Heavy Construction

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EARLY PROSODY.

629.

The prosody of the earlier poets differs in several respects from that of the later.[1][Before the Latin language was used in literature, it had become much changed by the loss of final consonants and the shortening of final syllables under the influence of accent. In many cases this change was still in progress in the time of the early poets. This tendency was arrested by the study of grammar and by literature, but shows itself again in the Romance languages.]

a. At the end of words s, being only feebly sounded, does not make position with a following consonant; it sometimes disappeared altogether. This usage continued in all poets till Cicero's time (§ 15. 7).

b. A long syllable immediately preceded or followed by the ictus may be shortened (iambic shortening): -

1. In a word of two syllables of which the first is short (this effect remained in a few words like puta, cave, vale, vide, ego, modo, duo[2][Cf. ambó (also a dual, p. 59, footnote), in which the ó is retained because of the length of the first syllable.]): -
- abi (Ter. Ph. 59); boni (id. 516); homo suavis (id. 411).
- 2. If it is either a monosyllable or the first syllable of a word which 2. is preceded by a short monosyllable: -
- sed has tabellás (Pl. Pers. 195); quid hic nunc (id. Epid. 157); per inpluvium (Ter. Ph. 707); ego ostenderem (id. 793).
- 3. When preceded by a short initial syllable in a word of more than three syllables: -
- - venustatis
  (Ter. Hec. 848); senectutem (id. Ph. 434); Syracus=as (Pl. Merc. 37); amicitia (id. Ps. 1263).
c. In a few isolated words position is often disregarded.[3][Scholars are not yet agreed upon the principle or the extent of this irregularity.] Such are ille, immo, inde, iste, omnis, nempe, quippe, unde.
d. The original long quantity of some final syllables is retained.
1. The ending -or is retained long in nouns with long stem-vowel (original r-stems or original s-stems): -
- modo quom dicta in me ingerebás odium non uxor eram (Pl. Asin. 927).
- ita mi in pectore atque corde facit amor incendium (id. Merc. 500).
- atque quantó nox fuistí longior hác proxuma (id. Am. 548).
2. The termination -es (-itis) is sometimes retained long, as in mílés, superstés.
3. All verb-endings in -r, -s, and -t may be retained long where the vowel is elsewhere long in inflection: -
- regredior audisse me (Pl. Capt. 1023); atque ut qui fuer=is et qui nunc (id. 248); m=e nominat haec (id. Epid. iv. 1. 8); faciat ut semper (id. Poen. ii. 42); =infusc=ab=at, am=ab=o (cretics, id. Cist. i. 21); qu=i amét (id. Merc. 1021); ut fit in bell=o capitur alter filius (id. Capt. 25); tibi sit ad me revisas (id. Truc. ii. 4. 79).
e. Hiatus (§ 612. g) is allowed somewhat freely, especially at a pause in the sense, or when there is a change of speaker.[4][The extent of this license is still a question among scholars; but in the present state of texts it must sometimes be allowed.]