Is grammar really that important?
Is grammar really that important? Something to think about.
40 Answers
As several people have already mentioned, the answer depends on the meaning of the terms. Grammar--the set of synatactic and morphological rules--certainly is essential to successful communication, whereas the study of grammar may not be: complying with the rules is possible without being able to enunciate them. 'Fluency' is often used to refer to conversational competence or to an effortless and polished flow of spoken words. We all aspire to this level in any language that we speak (except perhaps dead languages), but we usually want to achieve more. We've all met fluent speakers of a language who are not literate. We hear people speaking with very few syntactic or morphological errors whose utterances, on a semantic level, are confused or nonsensical. We hear conversations by fluent speakers which contain grammatical errors, but we realize that on their level of discourse the errors aren't seriously interfering with communication. At some level of error or complexity, it will. The written language--outside of cyberspace--may require a higher grammatical standard. The ideas discussed and the syntax employed often raise our grammatical expectations or increase the number of grammatical hazards making grammatical errors even by totally fluent speakers far more likely. We have to wonder if studying grammar would reduce the error rate or improve the communication. In some of the examples that people have used, 'fluency' pertained to the spoken language, so orthography would never be an issue. Neither studying grammar nor totally immersing oneself in a language guarantees correct grammar, but immersion probably improves the odds of fluency. I think that the grandfather in the videos was making a more modest point than he thought.
I have a daughter who knows very little of the basics of English grammar. That is she doesn't know why she constructs her sentences the way she does. I imagine she just acquired an "ear" for it within the scope of her vocabulary - most of which she just absorbed rather than studied. Not to find fault with that, I think most of us learned to speak and even write before we knew any grammar. I judge she communicates effectively in informal English even though she doesn't know a preposition from an indirect object or a main clause from a dependent one. I recall that we used to diagram sentences in English back in the 40's and 50's. She - a college graduate - claims she never heard of such a thing.
Yet, she was employed as an English teacher in Japan for two years. I can understand how a child can pick up enough language to begin to communicate a little and gradually increase their ability to do so as they grow older. I was stationed in Japan for a couple of years in the Air Force and even though I didn't purport to study Japanese while there - I did learn a few useful phrases to help me find my way around. But I do not see how it is possible to get a good understanding, let alone be able to speak and/or write a non-native language within the span of a year or two without at least a modest knowledge of its grammar.
Consequently, I can only guess, because I don't know, that my daughter "taught" only those phrases (memorized) which we commonly see in tourist preparatory "courses."
Great points Lazarus! 
Although I find the study of grammar fascinating in relation to the languages I can speak I agree that any attempt by an individual to analyse what they should say when talking in real time with others will simply hinder any attempt to learn to communicate clearly and bore their listeners at the same time as they wait for the speaker to work out what to say!.
There is a place for studying grammar and desiring to achieve grammatical accuracy and that, I believe is in the learning process: either as the student studies the language in their private studies or perhaps within a private lesson with a language tutor and then to apply as much as they can remember when holding a conversation...but not to worry if they forget things or make mistakes.
I speak as someone who has followed both approaches: In the past when I was learning I have tried too hard to 'get it right' - perhaps for fear of making silly mistakes and ending-up looking stupid until I began to realize that native speakers don't care if we speak their language perfectly as long as we can clearly communicate the heart of what we are trying to say, I still make mistakes when I speak Spanish, French Portuguese or any other language I am learning even when applying what I already know, but I believe that I am able to speak Spanish with more fluency than a little 1 under year ago when I first joined SpanishDict
Finally, I would add that when you begin to help teach natives from other countries any language you can speak fluently, either formally or informally, it helps you to understand and appreciate your own language in a deeper way. I am helping a Columbian girl with her English while she helps me with My Spanish. Language Exchanges are a wonderful way to learn while at the same time making friends
This thread is starting to remind me of an old story about two Japanese men who spoke no English who went to see a play in London. Knowing that he wouldn't understand anything that was said, one of them decided to watch the machinery that worked the sets and understand how it worked--by the end of he play, he had pretty much figured it out. The other decided to try and get a feel for what was happening in the play, all the while understanding he would miss most (if not all) of the nuances and details.
At the end of the play, which one do you think understood it better?
Ironically, in the last video the guy was arguing smugly about his grandchild not being provided with grammar books or lessons when he'll be learning to speak, and then he inadvertently gave an example of him getting a rudimentary grammar lesson from his mother.
Priceless!
Well, now that I have forgotten so much of what I had learned I would dearly love to have it back. I am the type of person that wants to know the 'reason' or at least be vaguely aware of the reason... (What a tan!) 
Grammar while learning a language is like building a house. The grammar is the framework. Vocabulary is the walls and floors. Grammar is something to use to hold all of the vocabulary kind of.
Absolutely. It is that important.
Simple answer to this - yes, because depending on where the words are in the sentence and the grammar, the sentence can mean something totally different from what you wanted.
I can't believe that some of us think that it is not that important. If you want to speak properly, yes yes Y E S. If you just want to get by, be understood, ok, but you will never achieve well-spoken native level with bad grammar.
