Check out Adjectives Don’t Show Number in English by rogersgeorge. Here is an excerpt:
In a lot of languages, when you put an adjective with a noun, the adjective has to agree with the noun. Feminine nouns get feminine endings on their adjectives (gender), plural nouns get plural adjectives (number), and so on. If you know other languages, you know what I mean by the “and so on,”…
The full article is available here.
