Allen & Greenough · Part First — Words and Forms › Orthography

§15. Phonetic Changes

Among the main features in the changes of Latin from the earliest stages of the language as we know it up to the forms of classical Latin may be mentioned the following:—

Vowel Changes

The old diphthong ai became the classical ae (aedīlis for old aidīlis), old oi became oe orū (ūnus for old oinos), and old ou became ū( dūcō for old doucō).
In compound verbs the vowel a of the simple verb often appears as i or e, and ae similarly appears asī:—
- faciō, factum, but cōnficiō, cōnfectum; caedō, but occīdō, and similarly cecīdī, perfect of caedō (cf. cadō,occidō;cecidī, perfect of cadō).
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.
Two vowels coming together are often contracted:—
- cōgō for †co-agō; prōmō for †pro-emō;nīl for nihil; dēbeō for †dē-hibed(† dē-habeō).

Consonant Changes

An old s regularly became rbetween two vowels (rhotacism), passing first through the sound of (English) z:—
- eram (cf. est); generis, genitive of genus.¹
  ¹ A similar change can be seen in English: as, were (cf. was), lorn (cf. lose).
Note.—Final ssometimes became r by analogy: as,honor (older honōs), from the analogy of honōris, etc.
A dental (t, d) often became s, especially when standing next to t, d, or s: as,equestris for †equettris, cāsus for †cadtus (cf. 6, below).
Many instances of assimilation, partial or complete, are found:—
- cessī for †ced-sī; summus for †supmus; scrīptus for scrībtus(b unvoicing to p before the voiceless t); and in compound verbs (see § 16).
Dissimilation, the opposite kind of change, prevented in some cases the repetition of the same sound in successive syllables:—
Thus, parīlia for palīlia (from Palēs); merīdiēs for †medīdiēs; nātūrālis with suffix -ālis (after r), but populāris with -āris (after l).
Final s was in early Latin not always pronounced; as, plēnu( s) fidēī.
Note.—Traces of this pronunciation existed in Cicero's time. He speaks of the omission of final s before a word beginning with a consonant as “countrified” ( subrūsticum).
A final consonant often disappears: as, virgō for †virgōn;lac for †lact; cor for †cord.
G, c, and h unite with a following s to form x: as, rēx for †rēgs; dux for †ducs; trāxī for †trahsī.²
² Really for †traghsī. The hof trahō represents an older palatal sound (see § 19).
G and h before t becomec: as, rēctum for †regtum; āctum for †agtum; trāctum for †trahtum.³
³ Really for †traghtum. These are cases of partial assimilation (cf. 6, above).
Between m and s or mand t, a p is often developed: as, sūmpsī for †sūmsī; ēmptum for †ēmtum.

J. H. Allen and J. B. Greenough, New Latin Grammar (Boston: Ginn, 1903). Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities.