37.  There are three ways of changing the singular form to the plural:—­

(1) By adding _-en_.

(2) By changing the root vowel.

(3) By adding _-s_ (or _-es_).

The first two methods prevailed, together with the third, in Old English, but in modern English _-s_ or _-es_ has come to be the “standard” ending; that is, whenever we adopt a new word, we make its plural by adding _-s_ or _-es._

I. Plurals formed by the Suffix _-en_.

[Sidenote:  The -en inflection.]

38.  This inflection remains only in the word oxen, though it was quite common in Old and Middle English; for instance, eyen (eyes), treen (trees), shoon (shoes), which last is still used in Lowland Scotch. Hosen is found in the King James version of the Bible, and housen is still common in the provincial speech in England.

39.  But other words were inflected afterwards, in imitation of the old words in _-en_ by making a double plural.

[Sidenote:  -En inflection imitated by other words.]

Brethren has passed through three stages.  The old plural was brothru, then brothre or brethre, finally brethren.  The weakening of inflections led to this addition.

Children has passed through the same history, though the intermediate form childer lasted till the seventeenth century in literary English, and is still found in dialects; as,—­

     “God bless me! so then, after all, you’ll have a chance to see
     your childer get up like, and get settled.”—­QUOTED BY DE
     QUINCEY.

Kine is another double plural, but has now no singular.

     In spite of wandering kine and other adverse
     circumstance.—­THOREAU.

II.  Plurals formed by Vowel Change.

40.  Examples of this inflection are,—­

man—­men foot—­feet goose—­geese louse—­lice mouse—­mice tooth—­teeth

Some other words—­as book, turf, wight, borough—­formerly had the same inflection, but they now add the ending _-s_.

41.  Akin to this class are some words, originally neuter, that have the singular and plural alike; such as deer, sheep, swine, etc.

Other words following the same usage are, pair, brace, dozen, after numerals (if not after numerals, or if preceded by the prepositions in, by, etc, they add _-s_):  also trout, salmon; head, sail; cannon; heathen, folk, people.

The words horse and foot, when they mean soldiery, retain the same form for plural meaning; as,—­

     The foot are fourscore thousand,
     The horse are thousands ten. 
     —­MACAULAY.