16. The plural number of nouns, that is, the form which indicates
more than one person or thing, is made by adding "-j" to the noun, as
"viroj", men, from "viro", man; "tabloj", tables, from "tablo", table.
[Footnote: "-oj" is pronounced like "oy" in "boy". See 5.]
17. An adjective modifying a plural noun agrees with it in number, being
given the plural form by the addition of the ending -j. An adjective
modifying two or more nouns used together is of course given the plural
form:
bonaj viroj, good men.
grandaj cxevaloj, large horses.
belaj birdo kaj floro (bela birdo kaj bela floro),
beautiful bird and (beautiful) flower.
[Footnote: "-aj" is pronounced like "ai" in "aisle". See 5.]
18. The article is invariable, that is, does not change in form when
used with plural nouns, as "la viro", the man, "la viroj", the men. The
verb is also invariable in form:
La viroj marsxas, the men walk, the men are walking.
La suno kaj la luno brilas, the sun and the moon are shining.
La viro estas, the man is.
La viroj estas, the men are.