1. Tense Categories of the English Language

6. / 27. Grammatical category of number in English.
A grammatical category is a system of expressing of generalized grammatical meaning by means of paradigmatic correlation of grammatical form.
The category of number in the noun is expressed by the opposition of the plural form to its singular form.
The general rule for forming the plural of English nouns is by adding - the ending s(-es) to the singular. This way of the plural number is conventionally called productive since it is typical of the majority of English nouns: a doll - dolls, a wolf - wolves, etc. But there are some non-productive means of expressing the number opposition.
The following nouns form their plurals by changing the internal vowel(s) (this is a survival from old English): foot-feet, man-men, mouse-mice, tooth-teeth, woman-women. Other survivals from the past are a few nouns which form their plurals with -en: brother - brethren, child - children, ox - oxen. Some nouns are homonymous in singular and plural forms:
sheep, deer, fish. A number of foreign nouns have retained their original plural endings: curriculum - curricula, basis - bases, oasis - oases, matrix - matrices. A limited number of nouns may have both productive and non-productive plural forms: index - indexes - indices.
The nouns that are always treated as the plural belong to the group called pluralia tantum. Another group which comprises the nouns that are never used in the plural belong to singularia tantum. The category of number is purely grammatical category. There are two numbers – singular and plural. We know that Modern English is analytical, but talking about the Old English in is necessary to remember that it was synthetic. There were four cases (Nom, Gen, Dat, Acc) and a word had different endings for Singular and Plural forms in different cases.
There can be distinguished strong and weak declension of OE substantives. The strong declension includes nouns with vocalic stems (-a-, -o-, -i-, -u-) and the weak declension comprises n-stems only. There are also minor types.