Why is grammar important? Is it ok for people to just not follow it?
There is an issue that comes even before this one, which is: Why do we need to communicate? What`s the best way to do it?
As human beings, we are naturally social beings, and we want to share our existence with others. All our opinions, our preferences, our thoughts, our feelings, memories, are all inside of this beautiful machine called brain, and fortunately or unfortunately, we are the only ones who have access to it. Then, how are we suppose to share all of the things that are stored and being processed in our minds. The answer is: we communicate? We do have a few tools to do so, but they usually can be categorized either under body language, or actual languages (by this I mean verbal, written, …). Truth is, no form of communication will ever be able to transmit the complexity of our thoughts, but we try to get as close to it as possible (which is precisely the reason why human beings have developed communication techniques that go far beyond any animal behavior). So what do we do? We structure communication to be able to transmit as much information as possible to someone else.
If we are speaking to somebody, there are other resources one can use: intonation of voice, cadence, body language, gestures. But why should the lack of these resources jeopardize communication? It doesn`t. There are commas, question marks, exclamation points, suspension points, and a number of other resources that are meant to provide the reader with all the details he needs to fully comprehend a written text as well as one would comprehend a dialog. We have verb tenses to determine if this particular action you are talking about happened, is happening, usually happens, has been happening, is going to happen, should happen, should have happened…if you are not using the correct verb tense, you are not making yourself understood, and this is your fault, not the listener`s, for assuming the person should understand what it going inside your head. Take a deep breath and remember: For better or for worse, you are the only human being that knows what goes inside your mind.
Why are grammar rules different among different languages? Because each society has evolved in its own way, and in a certain way, every language reflects the culture of its place of origin or practice (this becomes less and less evident given globalization and the fact that many different countries with reasonably different cultures do speak the same language). Declinations in German show that it is important to know whether the person is the subject or the object of a phrase. In my language for example, this is given by the position of words in a sentence. In French there is the need of showing respect towards someone important simply changing the conjugation of the verb. This is not the way we do it in Portuguese. Most languages conjugate verbs, showing which person is exercising the action, in English you don`t have to. In Turkish, verb to be`s are dispensable, you just say the noun and the adjective. In English you need the verb to be. In Portuguese, verb to be is not enough, and we have two different words for it, one if it is temporary and another one if it is permanent. In English, it is important to know if things are countable or not, in a indigenous language in Latin America numbers don`t exist, only the word none, one, a few, a lot, and in Polish they have different kinds of plural. Some languages change things according to gender, others don`t. In some way, it does reflect the society, because we cannot possibly reflect the complexity of what we think and feel, so we must choose what to communicate, and the language gives as a set of tools to do so. Grammar is there to structure the language, and wise people will make use of it.
But, when is it ok do break the rules? A popular argument is that language is in constant motion, and ever changing. This is certainly true, because a language reflects the society and society is an ever changing organism. We have examples of languages that failed to follow society and died, like Latin. We have examples of languages that haven`t changed its structure in over 300 years, like French, and is a true nightmare for those who attempt to learn the writing rules, that no longer reflect the language it has become, coexisting almost as a parallel language to the spoken one. There are languages that change so fast it is hard to keep up with all the changes, and it then fails to offer an organized structure to support communication (a good example of that in language used in internet). So what is the limit? How will we know it is time to change, and adapt, or when it is time to stick to the old fashion rules that have greatly served us in its purpose of allowing communication. I don`t have a good answer for that, I know I am a big fan of speaking as correctly as I can, so that I can be understood. There is enough miscommunication in the world, and I don`t want careless employment of grammar rules to be another one of them.