Plural forms of Spanish adjectives

In English adjectives have no plural forms. However, in Spanish it is different. Adjectives must be made plural when describing a plural noun. For example:

(singular) El muchacho es aplicado.(The boy is diligent.)
(plural) Los muchachos es aplicados. (The boys are diligent.)

(singular) La muchacha es simpática.(The girl is nice.)
(plural) Las muchachos es simpáticas. (The girls are nice.)

The plural of adjectives, like the plural of nouns, is formed by adding -s if the adjective ends in a vowel, or -es if the adjective ends in a consonant.

(singular) simpática (nice)
(plural) simpáticas (nice)

(singular) azul (blue)
(plural) azules (blue)

Related article: Plural forms of Spanish nouns

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