Children sometimes manage to strangle themselves on the cords used for raising and lowering blinds. I was putting up some blinds the other day when Anita announced "Oh look, they come with an anti child strangling device". Now the meaning of what she said is critically dependent on where you put the hyphen: an anti child-strangling device is very different from an anti-child strangling device. The rules of grammar (including capitalisation and punctuation) are what allow us to interpret otherwise ambiguous sentences. They are the difference between helping your friend Jack, off his horse, and doing something that's probably illegal.
The two sentences "They ate the food that they liked" and "They ate the food, which they liked" mean different things, and a knowledge of the rules of grammar allows us to assign the right meaning to each. But these days, one or more generations of school-leavers are ignorant of these rules, which means that readers can't be sure of what the writer intends. I find that I have to assess writers' use of grammar, and only if I am confident in their usage can I decide what is intended. I recently threw out a book on the history of France ( from the Cambridge Illustrated History series, by Colin Jones) because I got tired of trying to work through the ambiguities, faulty vocabulary and lack of clarity in what the author was trying to convey.
Which brings me on to the curious concept of a grammar nazi, being someone who corrects another person's faulty grammar. Ignorance, unlike stupidity, doesn't have to be permanent, and is a matter of choice, given a reasonable level of intelligence. If I point out to you that the sentence "Its a nice day today" makes as much sense as "Hers a nice day today" unless I mentally correct the grammar, then I'm a grammar nazi. So if you tell me that 2+2=5 and I tell you it's not 5 but 4, I'm an arithmetic nazi? If you tell me that William the conk came over in 1065 and I say, no, it was 1066, I'm a history nazi? Curious.
I know I'm opening myself up to criticism of any grammatical errors that might appear in my blog posts past, present and future, but to be honest, I'd rather eat humble pie and be lifted from ignorance than stay in the dark. Not everybody, apparently, shares this view. Here's a picture of the blinds.