"If you spell things wrongly and punctuate things incorrectly," my old university lecturer used to say, "people will think you are stupid, even if you are not."
I sort of agree with him, though I'd say if you make spelling mistakes and punctuation errors, people will think you don't care enough to check it, which is probably worse (now is perhaps the time to confess that I once cancelled an appointment with a hairdresser because she'd made a spelling mistake on her leaflets).
But the point of grammar and punctuation isn't to stop you looking stupid, or to prove you care - it's to get your meaning across. Bad spelling, poor grammar, incorrect punctuation - they all confuse things. Put an apostrophe in the wrong place and something becomes possessive when you really meant more than one. Mix up two words that sound the same but are spelled differently and you change the whole meaning of your sentence. It's useful to know about verbs and nouns and adjectives, so your sentences make sense. Knowing the difference between the subject and object in a sentence stops you saying 'I' when you should say 'me' and that stops me wanting to kill you. You see? This stuff matters.
I realise not everyone's like me in their extreme affection for grammar. I understand that not everyone can rank their top three fave punctuation marks* but if the point of writing is to say something, then spelling, grammar and punctuation help you say it clearly. It's like bringing a blurred photo into focus.
Now, do you know what doesn't matter? Modal verbs. Subordinating conjunctions. Co-ordinating conjunctions. Noun phrases. In short, most of the stuff 10 and 11 year olds in England have been forced to memorise for their SATs tests this week.
I just took a sample test. I've got a degree in English language and literature, I've been a writer for two decades and I've published six novels. I know how words work. I scored 60%.
All the questions smacked of being things you'd learn for the test, then immediately forget and never have to use again and frankly I think it's more important kids leave primary school knowing the difference between they're, their and there, than whether a modal verb is showing possibility or certainty.
Forcing kids to learn this stuff - this useless, pointless, incomprehensible stuff - is a great way of ensuring they lose all interest in grammar. Hell, I'd lost interest by question five and I have a deep love of punctuation.
The best way to teach children how to use language properly is to let them use it. Let them read brilliant, wonderful exciting books. Let them draw comics and bring them to life by adding dialogue. Read them poems and let them watch Michael Rosen clips on YouTube. Listen to One Direction songs and pick out the rhymes (half rhymes are just as valid when written by Harry Styles as when written by WB Yeats). Watch Star Wars and talk about how we understand BB8 when he says nothing at all. Write stories. Write thank you letters. Write shopping lists. Write anything, just write.
These tests suck. They kill children's love of learning and they need to be stopped. Full stop.
* in case you're wondering, they are:
3 - Spanish question marks, when they put them upside down at the start of a sentence. I can't even speak Spanish.
2 - Oxford comma.
1 - Semi-colon.