The Allen and Greenough is still under construction;
so some links may not work quite the way you would expect.
6. Latin spelling varied somewhat with the changes in
the language and was never absolutely settled in all details.
Thus, we find lubet, vortó,
as earlier, and libet, vertó
later forms. Other variations are optumus and optimus,
gerundus and gerendus.
The spelling of the first century of our era, known chiefly from
inscriptions, is tolerably uniform, and is commonly used in modern
editions of the classics.
a. After v (consonant u), o was
anciently used instead of u (voltus, servos), and this spelling was not
entirely given up until the middle of the first century of our era.
b. The older quo became cu in the Augustan period; in the second
century of our era the spelling quu
established itself in some words: -
- cum, older quom;[The spelling quum is very late and without authority.]
equos, ecus later equus; sequontur, secuntur, later sequuntur; similarly exstinguont, exstingunt, later exstinguunt.
- NOTE: In most modern editions the spelling quu is adopted, except in cum.
- c. Between consonant i and a preceding a,
e, o, or u, an i was developed as a transient sound, thus
producing a diphthong ai, ei, etc.,
before the consonant i. In such cases
but one i was written: as, âió (for ¥ai-ió), mâius (for ¥mai-ius), pêius (for ¥pei-ius).
- d. Similarly in compounds of
iació but one i was written (as, con-ició, not con-iició); but the usual pronunciation
probably showed consonant i followed
by vowel i (see §11.e).
- NOTE: Some variations are due to later changes in Latin
itself, and these are not now recognized in classical texts.
- 1. Unaccented ti aud
ci, when followed by a vowel, came to
be pronounced alike; hence núntió was later spelled with a
c and dició with a t.
- 2. The sound of h was after
a time lost and hence this letter was often omitted (as, aréna for haréna) or mistakenly written (as, humor for úmor).
- 3. The diphthong ae early in
the time of the Empire acquired the value of long open e (about like English e in there), and similarly oe after a time became a long close e (about like the English ey in they); aud so both were often
confused in spelling with e: as,
coena or caena for the correct form céna.