4.8.1. Vocalism in the Plural is generally the same as in the Singular. In Nominative-Vocative and Accusative, the straight cases, the full vowel grade is general (there is no Nominative with lengthened vowel), and in the Genitive the zero-grade is general. But there are also some special situations:
1. In the Nom.-Voc. there examples of full vowel: stems in -ei-es and -eu-es (-i, -u stems), in -er-es, -or-es, -en-es, -on-es, -es-es, also in words like pod-es.
2. Sometimes, the vowel timbre varies; as, akmen/kamen, (sharp) stone, which gives lit. akmuö / akmenes, osl. kamy / kamene.
3. There are also some cases of Ø-grade vowel: cf gr. oies. Also some analogical forms gr. kunes, lat. carnes.
4.8.2. The Ø-grade, an exception in the Nom.-Voc., is usual in Accusative Plural in -i, -u stems; as in derivatives with forms -i-ns, -u-ns.
Apart from this stems, it has generally a full vowel: akmenes, materes.
4.8.3. The stems in -s in the Nom.-Acc.-Voc. Plural Inanimate present -es-a, -e-s-a: they follow the vowel timbre in the whole inflection, but for the Nom.-Acc.-Voc. sg. in -os. The rest are in -Ø.
4.8.4. The general vocalism of the Genitive Plural is Ø. But the full grade is sometimes found, too; as in akmenom. The most common stems in which the full grade can be found are -n and sometimes -r; as in matrom, which could also be materom.
To sum up, Nominative Plural is usually opposed to Nominative Singular, while Genitive and Accusative tend to assimilate Singular and Plural. When the last are the same, full vowel is found in the Accusative, and Ø in the Genitive.
4.8.5. In the Obliques, where there is a distinction, the form is that of the Nominative Singular Animate or Nom.-Acc.-Voc. Singular Inanimate; and when, in any of them, there is a distinction between full- and Ø-grade, they take the last. An example of Animates is pod, which gives: Nom. pods, Gen. podos, Obl. Plural podbhis. In Inanimates it happens with -s stems which have -os in Nom.-Acc. and -es in the other cases; as in genesi, genesibhos. And in Heteroclites that oppose an -n in the cases that are not Nom.-Acc.-Voc. with -r, -s or -Ø.
The zero-grade in the predeclensional syllable is very common, wether it has the Genitive vocalism or the full one; as, kwon/ kunsi. This Ø-grade is also found in -r stems, as in patrosi/ patromos, patrobhos. And so in -i and -u stems, too, in Nom. and Acc. sg., while e is otherwise found (in Nom. pl., and sometimes in Gen. sg. and pl.). The Obliques Plural have Ø; as, egnibhios/ egnisi/ egnibhis; ghostimis,