Grammar is an important part of understanding how to use language correctly, however, there is sometimes a misconception that grammar is the be-all and end-all of language. The truth is, language isn't just about grammar rules - it is also about conveying meaning and making your point clear. This means that while it is important to know the rules of grammar in order to communicate effectively, the main purpose of language is to communicate something, not to simply "sound correct".
Grammar is not the only factor in understanding language. There are other linguistic elements that play a role in conveying meaning, such as tone of voice, body language, and context. For example, if you're speaking to someone in a casual setting, you may be able to get away with making small mistakes in grammar, if they understand the meaning of what you are saying. It's also important to remember that language is constantly evolving and that there is no one "right" way to say something.
In short, while grammar is an important part of understanding how to use language effectively, it's not the only factor. Other elements such as tone of voice, body language, and context also play their part in conveying meaning. The main purpose of language is to communicate something, so as long as your meaning is clear, grammar does not have to be perfect for effective communication.