History of the english language

The Strong Declension
includes nouns that had had a vocalic stem-forming suffix. Former suffixes (a,o,i,u) are no longer found in Old English, moreover, even very paradigms of these groups of nouns were already splitting .
-a-stems
They may be either masculine or neuter. The difference between the two genders may be seen only in the nominative.
Old English nouns a-stems neuter with long vowel might give an unchanged plural, and the noun sheep being an exception from the general rule of formation the plural form goes back to the Old English period.
Examples of Old English а-stems are: masculine: earrn (arm), eorl (earl), , biscop (bishop), heofon (heaven) etc.
neuter: word (word), bearn (child), feoh (cattle),hūs (house).
There are some peculiarities of declension of the nouns that had originally -j- or -w- in the stem (they are called -ja-stems and -wa-stems); they may preserve this sound in declension; but otherwise the differences are minor.
Examples of -ja- stems are: hyse (young warrior), fiscere (fisherman), net (net), bedd (bed).
The nouns belonging to ō -stems are all feminine. In the form of the nominative case monosyllabic nouns with a short root vowel of this class have ending –u; if there are two and more syllables or the root vowel is long, there is no ending at all:
The nouns of this group: caru (care), scamu (shame).
In this group of nouns the suffix - ō - may also be accompanied by additional і and w, that is -jō - and -wō - stems will give variants of declension.
The nouns formerly having -i-sufix, now called -i-stems might belong to all the three genders, and the case endings are different for different genders - masculine and neuter have the same endings as masculine and neuter nouns of the -a- stems, and feminine noun endings repeated the endings of the -o-stems.
The nouns of this group are: masculine: mere (sea), mete (food); neuter: sife (sieve), hilt (hilt); feminine: wiht (thing), hyde (hide), woruld (world, age).
Nouns belonging to -u-stems may be of masculine or feminine gender:
The nouns of this group are:masculine: wudu (wood), medu (honey); feminine: nosu (nose), hand (hand).