[rewboss]

riverkid, why do you have to turn everything into a battle about prescriptivism versus descriptivism?

His definition is precisely what The Grammar Book, a respected ESL grammar uses.

Well, I disagree with The Grammar Book. I've pointed out what I believe to be a weakness in that definition: it's far too simplistic and simply doesn't match reality. You haven't addressed that with anything more than appeal to authority, which is a logical fallacy and always a very weak argument.

I'm not aware of any dialect of English that actually has a rule, a real rule that is, where double negatives cancel each other out to form a positive. Perhaps you could point one out for us?

How can you, who claims to believe in descriptivism, demand to see "a rule", and then qualify that by saying "a real rule"? What do you regard as "a real rule"? For a huge number of speakers, a double negative is generally a positive, such as the dialects spoken in southeast England, on which RP is partly based. In a large number of dialects, speakers do not use double negatives, or use them only as negated negatives (slightly different from a straight positive, of course, but I was simplifying for clarity).

If this was to appear in a technical manual, every native speaker of English would know that it was a typo

How would they know if it's perfectly grammatically correct? Are you saying that technical manuals follow different rules of grammar? If so, why are you even arguing with me?

I can't imagine any person, even the most prescriptive, thinking that the two negatives mean that a person should supply hydrogen gas to the outlet

Perhaps that's because such a construction doesn't exist in your dialect. Maybe it exists in mine. Do you know all English dialects? I mean, do you really?

These unhelpful statements have been repeated for so lomg by prescriptivists that they have, for some, taken on the qualities of a mantra.

No, this is your mantra; it has become so because every time somebody says something you personally disagree with, you claim that it's "prescriptivist" and therefore "wrong". It is by way of a knee-jerk reaction with you: "This is a silly prescriptivism", "Prescriptivists have always claimed this, but they're wrong" -- and yet the fact remains that for a large number of native speakers of English, a double negative is not a negative. There's no "right" or "wrong" here; there are dialects of English that treat double negatives differently. The error would be to suggest that one way is "correct" and the other is "incorrect" -- that is the fallacy. They are all correct within their own dialects.

A tin ear for stress and melody...

I'd like to see Pinker use that argument for written English. Punctuation and italics can only give a rough clue as to intonation, stress and melody.

That Standard English better facilitates communication is a complete falsehood, Rewboss. People communicate perfectly well in their dialects, at least as well, if not better using nonstandard forms.

People communicate perfectly well within their dialects, but between dialects is an entirely different matter. I would be very surprised indeed if you could understand a broad Geordie dialect, as spoken in the Tyneside area of northeast England. Even most British people have trouble with it. It may well be that "yakkin Geordie is mint", but you'd never write a technical manual or even a novel in Geordie. (You might write a novel in standard English with some well-known Geordie dialect words and a few spellings to indicate a Geordie accent, but that's not the same.)

And why wouldn't you write a book in real Geordie? Not because there's anything inferior about Geordie, but because people in Cleveland, Auckland or even Birmingham, England would have difficulty understanding it. Write it standard English, or even standard English with variations, and it instantly becomes accessible to all. I hope it is not your contention that someone from Newcastle can make himself better understood by a New Yorker if he spoke Geordie instead of Oxford English.

People who have not been raised on prescriptions still use Standard English for writing and for formal speech. They use it not to communicate any more effectively but simply because that is what we use.

That depends on the person. Skilled speakers use standard English in formal settings precisely because they wish to be understood by a wider audience. When Trainspotting was released in the US, the actors dubbed their lines into a more US-friendly dialect so that Americans could actually understand what was being said. They retained some Scottish speech patterns, but moderated their accent to something very much closer to Oxford English -- a sort of "The engines canna take it, Cap'n" dialect. If Billy Connolly were to perform in his native Glaswegian accent, I confidently predict you would not understand half his jokes. My wife speaks the Kahlgrund dialect with family and neighbours, and High German with everybody else (including me), and will happily tell you that she deliberately speaks High German to me for my benefit: like most people, she is bilingual within her own language.

Indeed, before the mass media "ironed out" some of the most obvious differences between dialects, the situation was even worse: even neighbouring dialects could be mutually unintelligible. When radio first brought American English to the ears of ordinary Brits, many hardly recognised it as English at all, let alone understood what was said.

Again, there is no need for prescriptive grammar; there actually isn't any need for prescriptive grammar for descriptive grammar accurately describes how language is used in all registers.

I'm not using prescriptive grammar to describe how language is used. Indeed, I expressly made the point that prescriptive grammar is nothing but an artificial set of agreed standards. You're falling into the trap of thinking that there is a war between prescriptive and descriptive grammar (a trap that an awful lot of self-styled "grammarians" on both sides of the argument fall into), when in fact it's a case of different tools for different jobs.