Grammar (noun): the structure and system of a language, or of languages in general, usually considered to consist of syntax and morphology.
Grammar is the system of a language.

Do we need to study grammar to learn a language? If you are serious about learning a foreign language, the long answer is "yes, grammar can help you to learn a language more quickly and more efficiently." It's important to think of grammar as something that can help you, like a friend. When you understand the grammar (or system) of a language, you can understand many things yourself, without having to ask a teacher or look in a book.

So think of grammar as something good, something positive, something that you can use to find your way - like a signpost or a map.

Good luck!