The importance of English Grammar

Nowadays, it seems to me that the structures of English grammar have changed. Academically speaking, certain expressions or sentence structures which were considered wrong in the past are now pleasantly accepted as correct by many experts of English. For example, it was wrong to say: " Everybody played their role ( they) in the past, but now it is grammatically acceptable. Even now, the use of " due to " to begin a sentence is widely used ( even in the UK, Australia, N.Z, US, West Indies, Malta, India, Singapore, Ireland, Pakistan ).
 Another obvious structure is the mixture of British and American English structures in written English. e.g. the use of "color", program, " accommodations " ( American English ).

My concern is : If this mixture were to exist in the next 100 years, I 'm afraid that learners of English might be exposed to confusion to see which structure is better than the other. Furthermore, the grammatically-acceptable sentences may not play a pivotal role in modern writing.I can see this scenario even in academic writing or journal.
grammar is still important. Sentence construction, as we know it, relies on grammar to make it comprehensible.

However, with the growing trend towards text-speak and chat-speak, it is inevitable that English will undergo changes in the next 100 years, just as it has since earliest times.

"I will see you later on."

"c u l8r"

Thank goodness we have records of the works of such writers as Chaucer and Shakespeare, together with the classical poets. Their writing is unsurpassed and has delighted millions of people.

What the poetry of the future will be like I can't imagine. Maybe if I get to Heaven I'll be able to hear it. I hope so.
I do not whether there will be a correct English for the world in the future.
English has undergone three transitional periods : Old English ; Middle English and Modern English. The varied English structures now are the results of science and technology.
Grammar is important because it is the language that makes it possible for us to talk about language. Grammar names the types of words and word groups that make up sentences not only in English but in any language. As human beings, we can put sentences together even as children--we can all do grammar. But to be able to talk about how sentences are built, about the types of words and word groups that make up sentences--that is knowing about grammar. And knowing about grammar offers a window into the human mind and into our amazingly complex mental capacity.  People associate grammar with errors and correctness. But knowing about grammar also helps us understand what makes sentences and paragraphs clear and interesting and precise. Grammar can be part of literature discussions, when we and our students closely read the sentences in poetry and stories. And knowing about grammar means finding out that all languages and all dialects follow grammatical patterns. Imagine that: a document prepared by a committee (NCTE's Assembly for the Teaching of English Grammar) that doesn't sound like a committee. The voice, in fact, belongs to Brock Haussamen, professor of English at Raritan Valley Community College of New Jersey. And whether or not you teach English for a living, the full report.
We learn basic grammar when we start to put sentences together as children. But, the actual ‘knowing’ of grammar is much more complex. Grammar teaches us how to build sentences, about the types of words that we use and when we should use them. Grammar also tells us what type of word we are using in any particular sentence.
There are lots of different aspects to English grammar, and each is as important as the last. It is English grammar that will allow you to be a better communicator, listener, thinker, reader and writer. Having a knowledgeable understanding of grammar will let you have a potentially rewarding career in many fields of work.
From the explanation above, we can conclude that English Grammar is very important. As the English learners, we must study about it. There are so  many website that explain about it. Free Online English is one of the best websites that give so many explanations about English grammar.