Grammar is merely the description of rules that govern a language. Our knowledge of grammar means we understand the difference between “I gave it to you” and “you gave it to me.” Even if I say (as Tarzan might) “Me gave it to you”, we understand the meaning from the syntax (word order.) But if Tarzan said “me gave it you”, things get a little fuzzy because we lost the preposition “to” indicating the direction of the giving. If Tarzan’s first language uses a different syntax then he might have said “you gave me it”, with the belief he was expressing that to you he gave it. So knowledge of grammar rules helps us express ideas.
Many people argue these days that grammar is not important. After all, if you understand what I am saying, then what difference does an apostrophe make? The answer is not much, most of the time. People learn a second language and manage to communicate. I stumbled through Mexico city, took the bus to Oaxaca and back and negotiated numerous situations, all based on two years of listening to Spanish language podcasts. But I wasn’t able to talk about theories of teaching and learning. I couldn’t have discussed with a Spanish teacher Freire’s theory of the Pedagogy of the Oppressed. Knowledge of grammar allows us to express ideas precisely.
Knowledge of grammar makes the difference between “my dad’s car” (the car belonging to my dad) and “my dads’ car” (the car belonging to my two dads–or my dads are gay!). Precise language use respects the difference between prosecute, persecute, and execute, all of which I’ve seen used to refer to what happened to the Japanese people on the West Coast during WW2. Knowledge of grammar is one of the ways that you show that you know what you are talking about, because you can express your ideas precisely.
There’s something else that’s even more important about grammar. The famous Russian psychologist Lev Vygotsky believed that language is a fundamental part of cognition. What this means is that language is how we think. We think using words, and ideas are created out of language. So grammar not only matters for expressing your ideas, it matters for creating ideas as well.
This is relatively straightforward for ideas such as “I’m hungry” or “It’s time for me to go to work.” But if you want to pick up a book of philosophy, engineering, computer science, or history, you need to be able to deal with complex and subtle ideas. These can only be expressed precisely using precise grammar and vocabulary. To understand them requires an understanding of their expression.
Students often complain to me about studying vocabulary. When we teach that one word means the same as another word, they rightfully complain that there should only be one word. But this vast panoply of vocabulary comes to us because words often have slightly different meanings. Words can vary in connotation when they have almost the same denotation. A client asked me in my Free Grammar Help, the difference between “shout” and “scream”; upon reflection, I answered that I believe it is mostly in the quality of the emotion of the utterance.
But in advanced education, complex ideas are synthesized into specialized vocabulary expressed in precise ways. To navigate these waters, one must have excellent control over grammar. When I read a Ph.D. thesis for my thesis editing service, I don’t always understand all of the ideas being expressed. But, because I understand the grammar, I can precisely locate the ideas that I’m not familiar with and quickly find out about them. When I was studying learning disabilities, I had to do a lot of reading of published research about brain development and neurophysiology. It was my knowledge of grammar that allowed me to understand and build my own knowledge.
On a more fundamental level for most of us is that our knowledge of grammar affects (not effects) our credibility as students and businesspeople. As the bus bench ad above shows, one small grammar error can chip away at your credibility. Perhaps thousands wouldn’t have noticed the error. Thousands more wouldn’t care. But if you are going to go to the expense of buying advertising, why would you settle for something that has some fundamental flaw in it? The same goes for a resume or business letter. These errors reflect on your professionalism. If that real estate agent allows an error to go in his bus bench ad, could he allow an error in a contract? And could that error cost his client thousands of dollars? Would you want to take a chance?
So grammar matters for humans. Because humans (Homo sapiens) are fundamentally thinking beings. And thinking requires language. You show off your good thinking when you use good grammar.