From the Cockney rhyming calls of London's East End traders to teen speak, slang has always been part of Britain's rich and diverse language.

But young people are increasingly unable to distinguish when it's appropriate to use it, say some linguists. Their language is becoming saturated by slang, leaving them ill-equipped to communicate in the wider world.

Paul Kerswill, professor of sociolinguistics at Lancaster University, is studying street language in London. He says an entirely new dialect is emerging.

"Young people are growing up with a new form of composite language. It's a bit cockney, a bit West Indian, a bit West African, with some Bangladeshi and Kuwaiti - and it seems to be replacing traditional cockney."

This "multicultural English" is now the ordinary way of speaking for many young people, he says. Instead of just using it to be cool or to fit in with peers, they use it when they speak to everyone.

And those who use it are losing any sense of "appropriacy" - the important skill of turning it on and off in different situations.

"Appropriacy simply means using the right variety of language for the right context - using business jargon in business meetings, formal English in exams or slang in school playground," says slang expert Tony Thorne.

"Language isn't just about communication, there is a strong social, political and emotional charge to it."

Teachers warn of the damage caused by slang and its "sabotage" of literacy, he says.

Don't say 'innit'

But what is the answer? One school in Manchester is so concerned it has recently banned slang.

"It was clear many students found it difficult to get through a sentence without saying 'innit' or 'do you know what I mean'," says Maria Nightingale, principal for operations at the Manchester Academy.

"We're a business and enterprise academy. It is really important our youngsters go into the world equipped with the appropriate use of language so they are not disadvantaged."

Exam results have soared as a consequence, she says. So should such a ban be more widespread and if it was, would it work?

It's a ban that would be impossible to achieve, says Jamaican poet Benjamin Zephaniah.

"There's no official language police. When does slang become every day normal use, part of communication? I hear politicians 'bigging up' an organisation or charity - 'big up' comes straight from Jamaican. Ann Widdecombe said 'let me fix up' when she put on her microphone, that's Jamaican."

The very nature of English language - and what it means to be British - is its flexibility, he says.

"A long time ago slang was about work. Market workers, carpenters, public houses, farmers had their own slang. Now slang comes from people bringing new words from other languages.

"Zoo came from France, pyjamas from India, shampoo comes from Urdu. Television is part Latin, part Greek, yet we think of it as one word. The English language no longer simply belongs to the English, it's multicultural."

Slang is also a natural human tendency, says Mr Thorne.

"All groups - it doesn't matter whether they are soldiers, policeman, criminals or whatever - always generate to some extent their own language. It's not just to communicate information, it's in order to include people into your group and exclude people out of your group."

Slang has not become more prevalent, simply more public, he says.

"This kind of language has always been there, but it's been liberated. Even in the punk era in the 1970s and 80s, newspapers wouldn't print slang. Now there are very few constraints - in media, TV soaps, rap lyrics - it's much more in your face."

He said, she said

So if banning slang is not the solution, might the key be to understand it better?

That's the conclusion of one sixth form college in south London, which has put slang on the syllabus.

"A-level students learn where slang comes from," says Dan Clayton, a teacher at St Francis Xavier in Clapham. "They analyse it linguistically and think about what function it serves in conversations, as well as its links to identity."

Older generations - which tend to associate slang with the values of American gangster rap culture and social decline - would benefit from studying it too because it would make slang seem less alien, he says.

Education is essential, says Prof Kerswill, so people understand how different social groups speak, and how their language relates to ethnicity or social class.

"You can very quickly slip into the perception that there is good language and bad language, and then make the false link between bad language and bad people."

Talking about slang also reinforces a sense of appropriacy, much in the same way as political correctness has made people more sensitive to how language can hurt and discriminate, says Mr Thorne.

And all of us should learn how important it is to spot when slang is inappropriate, says Mr Zephaniah.

"Whether we like it or not, the way we talk affects the way people see us and this can have very serious consequences.

"I see slang like martial arts. So long as you have strong foundations, you are free to improvise."

Below is a selection of your comments.

I have absolutely no issue with slang. It's part and parcel of growing up. The thing that I do have an issue with is the number of 'typical' English kids who now seem to speak with these bizarre accents as standard. They are totally at odds with their surroundings and upbringing. If their grandparents were to hear them speaking like that they'd wonder what the hell had happened to them. Parents just have to take it on the chin and accept it as a phase. Will the kids of today still speak like this when they grow up? I'm sure some of the ones who do could well end up jobless. Mark, Bournemouth

Some words we use today as standard English started as slang, some words have different meanings today than they had 50 years ago. Slang and its slow progress into standard English is fine. The reason English is such a popular language is because it adapts well to fit the way it is being used. French does not, which is why there are so many English words now used in modern French. Germany actually changed their language and started teaching their children 'new' German some 30 years ago (new words in German used to be made by just putting older words together meaning some words were getting very long). They had huge problems with a generation gap where young and old used different words and probably still do. We should embrace the fact that our language is fluid. I am not suggesting children should be encourage to make up and use new words all the time, but accepting some of those new words into our everyday language is acceptable, just as removing some obscure words from the dictionary is fine. Janet, York

I'm a freelance interpreter. Some months ago I was speaking to the head of one of the UK's leading schools for training interpreters. She told me that their biggest problem - one which is growing with each new intake of students - is not necessarily what one might think, i.e: their knowledge of the foreign language from which they are supposed to be interpreting. It is the quality of the English into which they render it. It is frequently heavily contaminated by street slang, and they appear to have difficulty grasping the idea that the formal setting of an international diplomatic conference or business meeting requires a completely different register and quality of language. Rosemary Hill, Geneva, Switzerland

Most young people, and many an adult, uses some kind of slang. And for the most part, we know when it's right to use it or not. However, there are those who in every sense don't have the capacity to differentiate between the right time and the wrong time to use slang. Those people are usually the ones for whom learning is at best difficult, and just as with maths or any other academic subject, can't really grasp the English language. So don't knock slang - it's always been around and always will. Tony, London

Where does Benjamin Zephaniah get the idea that the word "zoo" came from France? It's just an abbreviation of "zoological". Perhaps he's thinking of "menagerie"? Stephen, Brighton UK

By all means let people speak slang in their peer groups, when I was younger we had made-up languages as well. What seems to have changed is the ability to recognise that it is completely inappropriate to use slang in a more formal setting. Perhaps if we made less effort to mollycoddle and "understand" and simply refused to acknowledge slang things might change? Briony, Bristol

Clearly you can't ban slang. But if a student of mine handed in work written in slang, they'd fail. Rick Webber, Brighton, UK

Public servants, at any level, should never use slang in their dealings with clients. It doesn't impress them and gives the impression you are uneducated. Using understandable standard English shows responsibility and encourages the public to have confidence in you. The other day, in a phone shop an assistant approached me and asked "Aw righ(t) ma(t)e?" I didn't purchase anything. Tony Cooley, Walsall

When we talk of soldiers, carpenters or farmers having there own slang, and they may well do, let us at least not confuse slang with jargon which serves a very useful purpose in allowing precise communication within a specific group. Language quite rightly evolves, as any schoolchild struggling with Shakespeare will be all too aware, so we shouldn't be too precious about "non-standard" uses of language. The problem however is that if one group adopts a new dialect, or slang, too quickly and forgets how to communicate in the old one then we have a potentially serious problems. John, Hamilton, Scotland

For hundreds of years social commentators have been berating the state of language in contemporary society and expecting total collapse of language and yet it hasn't happened. Language is not some monolithic structure but an evolving continuum and slang is simply avant-garde language that may or may not become part of the mainstream. I expect it is also happening to French, Spanish, German etc etc. Wicked, innit. Charles, Hereford

The vernacular has always existed, as has dialect. People should know/be taught when it's appropriate to use this (in informal settings) and when it's not (formal including the classroom and when written). Most people master this skill without any trouble. In my opinion, the classroom should be a formal setting and preclude slang. CAM, London

Any linguist who believes "appropriacy" is a word should be promptly returned to school and taught to speak English properly. The word is "appropriateness". In any case, this issue crops up once a generation, and probably has ever since language was invented. I can just imagine a Cro Magnon parent complaining about the Neanderthal slang the kids have picked up. Steve Bartlett, Hamilton, ON, Canada

"Appropriacy" - I had to laugh... But on a serious note, we are not teaching "appropriateness" any more - whether that is in speech, writing, dress or behaviour. Slang is fine in the right context, but it does seem that the more boorish you sound and behave, the more you are admired. Andy, Horsham, Sussex

"ap·pro·pri·acy noun [U] 1. the extent to which sth is suitable or acceptable 2. (linguistics) the extent to which a word or phrase sounds correct and natural in relation to the situation it is used in" (Oxford Advanced Learner's Dictionary, 7th edition) Iain Cunningham, Leamington Spa

We really ought to put a stop to this slang entering and ruining the English language, thereby becoming accepted as the norm; to do this, we should not be accepting these new words and terms into the Oxford English dictionary each year. Mark, Oxford

No you can't ban certain words. English became such a powerful language because of it's ability to morph and change. English is the thief of languages and has always been a bit dodgy. By all means allow the young folk to use their slang, but they must also know that there is a time and place for it. John, Glasgow

Something that no-one appears to have picked up is that if we allow anarchy in language, it becomes impossible to teach to other countries. That would mean that if we continue to trade we must embrace other languages ourselves, or become isolated. Sid Miller, Normandy, France

What annoys me more than anything is adults over 30 years old typing slang in text messages and on social networking sites. Slang when you are still at school is in away part of growing up, to continue into your 30s is pathetic and in my book shows a complete lack of intelligence. Ellie, Newbury, Berkshire

Ellie - I'm sure you must use some slang in day-to-day life. I bet you've used the term 'bankster' or 'chav'. I'm in my 20s and even I have great difficulty understanding some of my peers. I also can't imagine some of my friends being in professional business meetings because of how much they use slang. You complain about people in their 30s using slang on Facebook but this is fine as it is an appropriate place to use it. I'm also certain (at least I hope) they know which situations are appropriate to use slang. The biggest problem is my peer group don't know when it is appropriate. In fact, I have sympathy for them - they will continue to struggle in the working world if they are unable to speak formal and coherent English. Jamie, France

Unlike Ellie, most of us have grasped the point that slang exists as a social element, irrespective of age group. The oldest amongst us will still use slang words, even if these are more likely to be derived from their generation than their great-grandchildren's. It is not something you can stop, ban, control or legislate against, neither should you consider trying to fix a living language in this way, unless you enjoy exercises in futility. Some people use slang in 'textspeak' simply because it is quicker, but the language police out there might also like to consider that such texting slang is in its most appropriate setting. Appropriateness is the most important consideration in language, not a sterile dissection of the content itself. Liz, Warwickshire