Batavian/Etymological study

a-stem
Masculine a-stem nouns follow regular, weak declension patterns; neuter a-stem nouns normally follow an indeterminate plural, but internal vowel mutation is also present; CVVC → CVCe plural, CVVCs genitive.

ja-stem
The ja-stem is functionally identical to the a-stem, with a general trend towards umlauting stems but not alternation.

ōn-stem
Exclusively feminine, ōn-stem nouns are identical to a-stem nouns, except that their genitive forms are -e, not -s

Consonant stem
Consonant stems generally pluralize and genitivize with vowel alteration and or palatalization. Predominately masculine or feminine, but neuter consonant stems do exist.

i-stem
i-stem nouns are identical to ōn-stem nouns in function and form, except that i-stem nouns can be masculine and neuter, though the former is more common.

an-stem
Masculine an-stem nouns have, CVVC to CVCen plural and a genitive form with umlaut and -en. Neuter an-stems follow the same pattern, except the plural is -e only. The long-o in the nominative is likely inconsistent in Pre-Old Batavian.

īn-stem
Exclusively feminine, īn-stem nouns do not have any plurals, but their genitives are -en.

ō-stem
Exclusively feminine, ō-stem nouns show a final -e and sometimes vowel mutation in plural, and no mutation or suffix in the genitive.

u-stem
Both masculine and feminine u-stem nouns show vowel alternation in the stem or no change at all and the genitive is marked with a -e suffix. PWGmc suggests -iwi in the nominative plural, but this was likely reduced to -i in Pre-Old Batavian. Rarely, u-stem nouns were neuter, but they usually assimilate to masculine or feminine (e.g., *fehu → föch "livestock" was originally neuter, but is now masculine).

Class 1
Class 1 strong verbs demonstrate a historical -ī- in their root vowel, which does not cause palatalization in the past tense. A short vowel is present in the past participle.

Class 2
Class 2 strong verbs demonstrate a historical -eu- or -ū- in their root vowel. A short vowel is present in the past participle.

Class 3
Class 3 strong verbs demonstrate a historical short -i- or -e- in their root vowel followed by two consonants or one geminate. A short vowel is present in the past participle.

Class 4
Class 4 strong verbs demonstrate a historical short -e- in their root vowel. A short vowel is present in the past participle.

Class 5
Class 5 strong verbs demonstrate a historical short -e- in their root vowel. A medium vowel is present in the past participle.

Class 6
Class 6 strong verbs demonstrate a historical short -a- in their root vowel. A medium vowel is present in the past participle.

Class 7a
-ai-

Class 7b
-au-

Class 7d
-ā-

Class 7e
-ō-

Originally, the infinitive had a short -a-, but was made regular through association with the finite forms.