4.4.1. Third Declension

1. They are usually Animate nouns and end in -a, -ia [iə] / i / ia, -e, -o. Those in -a are very common, generally feminine in nouns and always in adjectives. Those in -ia/ i/ -ia are always feminine and are used to make feminines in the adjectival motion. Those in -o and -e are feminine only in lesser used words. Those in -a are etymologically identical to the Neuter plural in Nom.-Acc.-Voc.

Note. The entire stem could have been reduced to -a, because this is the origin of the whole stem system before IE III, even before the II stage of the language. We sacrifice clarity for a thorough approach, but that doesn't mean that the Third Declension cannot be named a-Declension, just as the Second is the Consonant Declension, or the Fourth is the Thematic Declension.

2. Europaio nouns of the Third Declension have thus the following model, with the exception of the -e, -o stems:

NOTE. Some argue (because of the obvious analogy with the other declensions) that the -ai in the Oblique could correspond to an older -aei or even -aei declension. This controversial issue is irrelevant for our system, though, as the situation we represent here is not that of the earlier stages of the language.

3. It is therefore identical to those in -r, -n, -s of the Second Declension, but for some details in vocalism: the Gen. has an -s and not -e/os; the difference between Nom. and Voc. is that of -a and -a. The Ø-grade of the Nom.-Acc.-Voc. in the -ia/-i themes is different from the Gen. in -ia.