4. We have already seen that y is not changed in derivatives when it is preceded by another vowel, as in the case of joyful, etc.; but we find exceptions to this principle in daily, laid, paid, said, saith, slain, and staid; and many write gaily and gaiety, though Webster prefers gayly and gayety.

5. Nouns of one syllable ending in o usually take a silent e also, as toe, doe, shoe, etc, but other parts of speech do not take the e, as do, to, so, no, and the like, and nouns of more than one syllable, as potato, tomato, etc., omit the e. Monosyllables ending in oe usually retain the silent e in derivatives, and we have shoeing, toeing, etc. The commoner English nouns ending in o also have the peculiarity of forming the plural by adding es instead of s, and we have potatoes, tomatoes, heroes, echoes, cargoes, embargoes, mottoes; but nouns a trifle more foreign form their plurals regularly, as solos, zeros, pianos, etc. When a vowel precedes the o, the plural is always formed regularly. The third person singular of the verb woo is wooes, of do does, of go goes, etc., in analogy with the plurals of the nouns ending in o.

6. The following are exceptions to the rule that silent e is retained in derivatives when the added syllable begins with a consonant: judgment, acknowledgment, lodgment, wholly, abridgment, wisdom, etc.

7. Some nouns ending in f or fe change those terminations to ve in the plural, as beef——beeves, leaf——leaves, knife——knives, loaf——loaves, life——lives, wife——wives, thief——thieves, wolf——wolves, self——selves, shelf——shelves, calf——calves, half——halves, elf——elves, sheaf——sheaves. We have chief——chiefs and handkerchief——handkerchiefs, however, and the same is true of all nouns ending in f or fe except those given above.

8. A few nouns form their plurals by changing a single vowel, as man——men, woman——women, goose——geese, foot——feet, tooth——teeth, etc. Compounds follow the rule of the simple form, but the plural of talisman is talismans, of German is Germans, of musselman is musselmans, because these are not compounds of men.

9. A few plurals are formed by adding en, as brother——brethren, child——children, ox——oxen.

10. Brother, pea, die, and penny have each two plurals, which differ in meaning. Brothers refers to male children of the same parents, brethren to members of a religious body or the like; peas is used when a definite number is mentioned, pease when bulk is referred to; dies are instruments used for stamping, etc., dice cubical blocks used in games of chance; pennies refer to a given number of coins, pence to an amount reckoned by the coins. Acquaintance is sometimes used in the plural for acquaintances with no difference of meaning.

11. A few words are the same in the plural as in the singular, as sheep, deer, trout, etc.

12. Some words derived from foreign languages retain the plurals of those languages. For example: datum——data criterion——criteria genus——genera larva——larvæ‎ crisis——crises matrix——matrices focus——foci monsieur——messieurs

13. A few allow either a regular plural or the plural retained from the foreign language: formula——formulæ or formulas beau——beaux or beaus index——indices or indexes stratum——strata or stratums bandit——banditti or bandits cherub——cherubim or cherubs seraph——seraphim or seraphs