Esperanto Grammar - Nouns and Adjectives

Nouns and Adjectives

A suffix -j following the noun or adjective suffixes -o or -a makes a word plural. Without this suffix, a countable noun is understood to be singular. Direct objects take an accusative case suffix -n, which goes after any plural suffix. (The resulting sequence -ojn rhymes with English coin, and -ajn rhymes with fine.)

Adjectives agree with nouns. That is, they are plural if the nouns they modify are plural, and accusative if the nouns they modify are accusative. Compare bona tago; bonaj tagoj; bonan tagon; bonajn tagojn (good day/days). This requirement allows for free word orders of adjective-noun and noun-adjective, even when two noun phrases are adjacent in subject–object–verb or verb–subject–object clauses:

la knabino feliĉan knabon kisis (the girl kissed a happy boy)

la knabino feliĉa knabon kisis (the happy girl kissed a boy).

Agreement clarifies the syntax in other ways as well. Adjectives take the plural suffix when they modify more than one noun, even if those nouns are all singular:

ruĝaj domo kaj aŭto (a red house and car)

ruĝa domo kaj aŭto (a red house and a car).

A predicative adjective does not take the accusative case suffix even when the noun it modifies does:

mi farbis la pordon ruĝan (I painted the red door)

mi farbis la pordon ruĝa (I painted the door red).