The most remarkable feature of OE nouns was their elaborate system of declensions, which was a sort of morphological classification. The total number of declensions, including both the major and minor types, exceeded twenty-five. All in all there were only ten distinct endings (plus some phonetic variants of these endings) and a few relevant root-vowel interchanges used in the noun paradigms; yet every morphological class had either its own specific endings or a specific succession of markers. Historically, the OE system of declensions was based on a number of distinctions: the stem-suffix, the gender of nouns, the phonetic structure of the word, phonetic changes in the final syllables.
In the first place, the morphological classification of OE nouns rested upon the most ancient (IE) grouping of nouns according to the stem-suffixes. Stem-suffixes could consist of vowels (vocalic stems, e. g. a-stems, t'-stems), of consonants (consonantal stems, e. g. n-stems), of sound sequences, e. g. -ja-stems, -nd-stems. Some groups of nouns had no stem-forming suffix or had a "zero-suffix"; they are usually termed "root-stems" and are grouped together with consonantal stems, as their roots ended in consonants, e. g. OE man, bōc (NE man, book).
The loss of stem-suffixes as distinct component parts had led to the formation of different sets of grammatical endings. The merging of the stem-suffix with the original grammatical ending and their phonetic weakening could result in the survival of the former stem-suffix in a new function, as a grammatical ending; thus n-stems had many forms ending in -an (from the earlier -*eni, -*enaz, etc.);
u-stems had the inflection -u in some forms.
Sometimes both elements – the stem-suffix and the original ending – were shortened or even dropped (e. g. the ending of the Dat. sg -e from the earlier -*ai, Nom. and Acc. pl -as from the earlier -ōs; the zero-ending in the Nom. and Acc. sg) in a-stems.
Another reason which accounts for the division of nouns into numerous declensions is their grouping according to gender. OE nouns distinguished three genders: Masc., Fem. and Neut. Though originally a semantic division, gender in OE was not always associated with the meaning of nouns. Sometimes a derivational suffix referred a noun to a certain gender and placed it into a certain semantic group, e. g. abstract nouns built with the help of the suffix -þu were
Fem. – OE len™þu, hyhþu (NE length, height), nomina agentis with the suffix -ere were Masc. – OE fiscere, bōcere (NE fisher, 'learned man'). The following nouns denoting human beings show, however, that grammatical gender did not necessarily correspond to sex: alongside Masc. and Fem. nouns denoting males and females there were nouns with "unjustified" gender, cf.:
OE spinnere, Masc. (NE spinner) – OE spinnestre, Fem. ('female spinner'; note NE spinster with a shift of meaning) and nouns like OE wīf, Neut. (NE wife), OE mæ™den Neut. (NE maiden, maid), OE wīf-man, Masc. (NE woman, originally a compound word whose second component -man was Masc.).
In OE gender was primarily a grammatical distinction; Masc., Fem. and Neut. nouns could have different forms, even if they belonged to the same stem (type of declension).
The division into genders was in a certain way connected with the division into stems, though there was no direct correspondence between them: some stems were represented by nouns of one particular gender, e. g. ō-stems were always Fem., others embraced nouns of two or three genders.
Other reasons accounting for the division into declensions were structural and phonetic: monosyllabic nouns had certain peculiarities as compared to polysyllabic; monosyllables with a long root-syllable (that is, containing a long vowel plus a consonant or a short vowel plus two consonants – also called "long-stemmed" nouns) differed in some forms from nouns with a short syllable (short-stemmed nouns).
The paradigms of nouns belonging to the main types of OE declensions are given in Tables 1,2 and 3.
The majority of OE nouns belonged to the a-stems, ō-stems and n-stems. Special attention should also be paid to the root-stems which displayed specific peculiarities in their forms and have left noticeable traces in Mod E.
a-stems included Masc. and Neut. nouns. About one third of OE nouns were Masc. a-stems, e. g. cniht (NE knight), hām (NE home), mūþ (NE mouth); examples of Neut. nouns are: lim (NE limb), hūs (NE house), þin™ (NE thing). (Disyllabic nouns, e. g. fin™er, differed from monosyllables in that they could drop their second vowel in the oblique cases: Nom. sg fin™er, Gen. fin™res, Dat. fin™re, NE finger.)
As seen from Table 1 the forms in the a-stem declension were distinguished through grammatical endings (including the zero-ending). In some words inflections were accompanied by sound interchanges: nouns with the vowel [æ] in the root had an interchange [æ~a], since in some orms the ending contained a back vowel, e. g. Nom. sg dæ™, Gen. dæ™es – Nom. and Gen. pl da™as, da™a. If a noun ended in a fricative consonant, it became voiced in an intervocal position, cf. Nom. sg mūþ, wulf - [θ], [f] - and Nom. pl mūþas, wulfas – [], [v]. (Note that their modern descendants have retained the interchange:, NE mouth—mouths [~θ], wolf—wolves, also house'—houses and others.) These interchanges were not peculiar of a-stems alone and are of no significance as grammatical markers; they are easily accountable by phonetic reasons.
Fem. – OE len™þu, hyhþu (NE length, height), nomina agentis with the suffix -ere were Masc. – OE fiscere, bōcere (NE fisher, 'learned man'). The following nouns denoting human beings show, however, that grammatical gender did not necessarily correspond to sex: alongside Masc. and Fem. nouns denoting males and females there were nouns with "unjustified" gender, cf.: