Did you see that great documentary on linguistics the other night? What about that terrific series on Radio 4 about the Indo-European language family tree? Or that news report on language extinction? It is strange that none of those programmes happened, or has ever happened: it's not as if language is an arcane subject. Just as puzzling is the conspicuous lack of a properly informed book about language – either our own or language in general.

There is, of course, Steven Pinker's The Language Instinct – a bestseller that seems to have ticked the box for publishers and public alike as the book on linguistics. But The Language Instinct has a very specific agenda – to support Noam Chomsky's theories about our language skills being innate; other areas of linguistics are glimpsed, if at all, fuzzily in the background.

I'm not blaming Pinker. He ultimately failed to justify his title, but he did reach a keen, large audience with a well-written book fizzing with ideas and examples. I'm blaming someone else, the person who, inexplicably, doesn't exist – who should have written the book revealing how Pinker was so wrong and had a ding-dong with him on Newsnight; the ambitious, good-looking academic, who possibly had a spell in an indie band, with his or her own 13-part series about language on BBC2.

I began to appreciate how little we know about our own language when I studied grammar to teach English as a foreign language. I looked for a linguistically informed grammar guide, but couldn't find one. Finally, I gave up on waiting and decided to have a go myself. As a layman with an amateur's adoration for his subject, I find it astonishing that hardly anyone outside university linguistics departments knows the slightest thing about it. Whether it is the new discoveries of neurolinguistics or the 150-year-old revelations of the scholars who traced the Indo-European language family tree, linguistics can offer zap-kapow findings that trump those of archaeology and even astronomy.

Take the Proto-Indo-Europeans, that mysterious tribe whose homeland was recently located north of the Caspian Sea in about 3,300 BC. Their language somehow obliterated the hundreds of others then spoken in Europe and northern India, so that almost every language currently spoken, from Iceland to the Himalayas, is descended from one tongue. Dramatic enough, but, even more sensationally, much of that language has been reconstructed, so that we know, for example, their words for sky (dyeu) and father (pihter), and their chief god the Sky Father (Dyeu Pihter). Thanks to language, we know a great deal about the tribe – its kinship system, its beliefs, the feasts it held at which bards declaimed the long praise-poems that may well be the forerunners of the Sanskrit Vedic epics and The Iliad and The Odyssey of Homer. We even know that the tribe had two words for different sorts of farting.

That few people have heard of the Proto-Indo-Europeans, or know about language evolution, children's language acquisition or the current process of language extinction, seems to me to be a crying shame. But the insights of linguistics are of social and political as well as intellectual importance.

The modern study of language has shown that all native speakers are experts in their language. Almost all judgments about someone's language – the laziness of a glottal stop, the slowness of rural speech, the supposed ugliness of a particular urban accent – have no linguistic justification and reflect only the prejudice of the judger. However, very few people are aware of these basic findings.

Linguistics has discovered that a language is created by a democratic collective of magnificently gifted experts – but has told nobody else about it. Frustrating as it is to hear discussions about the heinous abuse of "hopefully" or "disinterested", this public ignorance about language gets properly serious with the continuing discrimination against non-standard English.

Non-standard English is linguistically the equal of the standard version – in fact, dialects tend to be more sophisticated grammatically than standard (as in the plural "youse" of many non-standard dialects where standard has just one confusing form). Yet standard continues – even now – to be prized as the "correct" form, and any deviation is considered to be wrong, lazy, corrupt or ignorant.

This is most obviously the case in the education system. If a non-standard-speaking child persists in using non‑standard English, particularly non-standard grammar, that child will rarely progress. This is, of course, a class issue, standard English being the only dialect defined by socioeconomics rather than geography, and spoken by only 15% of the British population (the richest 15%). It is working-class children whose language is still marked as incorrect and who have to intuit the need to switch dialects – or fail..

In any formal, written context, only standard English is accepted. And in any informal, middle-class context, from office email to pub chat, non-standard usage will be noticed by standard speakers, who will judge that non-standard user to be at least unsophisticated, probably uneducated and very possibly a bit thick.

Let me quote a letter-writer to the Scotsman newspaper last year, complaining about declining linguistic standards. "I remember one candidate in a job interview," the letter-writer reminisced, "saying, 'Oh, we done that in media studies.' End of interview," he finished, approvingly.

Why has linguistics failed to counteract this discrimination? I put it down to the strange way that the discipline developed under the aegis of the man who has dominated and defined it since the late 50s, the father of modern linguistics, Chomsky.

Chomsky's theories were based on his ingenious explanation for the phenomenon that is children's language acquisition. Toddlers, who are surrounded by the broken babble of ordinary speech and who can do little else for themselves, somehow master many, or even most, grammatical constructions – because, Chomsky reasoned, there has to be innate software providing babies and toddlers with the equipment to get them up and talking. This means, he concluded, that human languages have to be organised according to universal constraints and rules, "principles and parameters". These constitute a "deep structure", converted into the individual operations of a particular language by a series of "transformations". Chomsky first outlined this idea in 1967 and has spent his non-political career since hunting for the universal features provided by our innate programming.

Brilliant – but wrong. Recent evidence from neurology, genetics and linguistics all points to there being no innate programming. Children learn language just as they learn all their other skills, by experience. The case against Chomsky is conclusive. The new empirical "connectionist" school and the various branches of cognitive linguistics have brought the subject back to scientific principles. Linguistics has undergone a revolution in the last 20 years, and Chomsky has been dethroned.

However, the wholesale acceptance of Chomsky's rationalist assumptions has meant that the discipline has been hunting for unicorns while neglecting many key areas of language. There is still little research being carried out on, for example, environmental influences on children's language acquisition.

Most pressingly of all, too little work is being done to record the languages currently facing extinction. By one estimate, 95% of the 7,000 languages now spoken in the world are in danger of dying out. Recording these should have been a priority.

Chomksy also played a significant part in creating a subject that managed to avoid engagement with culture and society. He turned grammar into an technical subject full of jargon and algebra studied on whiteboards by men with beards, leaving everyone prey to the pernicious drivel of the traditional grammar guardians, who belong to the 15%. It is crazy that such an unfair social-exclusion system should go on operating, and still without censure.

Linguistics has taught me many wonderful things, but it has also neglected many tasks, including telling the world about its discoveries. So if there is an academic linguist out there with good bone structure and a past career as a rhythm guitarist, please, for the love of God, get yourself a decent agent.