Here's why:
* Adjectives describe nouns: "Little" tells us more about a noun, like its size. For example: "a little dog" (describes the dog).
* Nouns name things: "Little" doesn't name anything on its own.
However, "little" can sometimes act as a noun in specific situations:
* Informal use: In informal language, "little" can refer to a small child, like "The little one is asleep."
* As a pronoun: In rare cases, "little" can replace a previously mentioned noun, like "The big dog was friendly, but the little one was shy."
So, while "little" is usually an adjective, its function can sometimes shift in specific contexts.