I was reading an interesting article in Saturday's Times, a regular column called The Pedant by Oliver Kamm. He's a writer and studier of English usage and one of the things he stresses is that there are both formal and informal forms of spoken English and that grammatical rules don't need to be followed strictly in the latter. He's quite lenient on the use of split infinitives an example being the famous opening to Star Trek.....'To boldly go where no man has gone before' He's ok with that simply because it is more fluid speech than saying 'To go boldly.........'

He had some interesting things to say about the use of 'innit'

Innit is actually a contraction of 'Isn't it' which in turn is a contraction of the more archaic 'Is it not'. This is known as an interrogative tag and our language is full of them. A few examples are Aren't there? Don't you? Haven't I? Shouldn't we? all quite grammatically correct. Amongst young people, Innit? has now become a more or less universal replacement for any of them, so we hear kids say things like 'We're going to the match innit?' I've gotta get a job innit? Even though to us they sound like very poor grammar, Kamm's point is that language is changing all the time and the use of innit is no more out of place in everyday English speech than the French use of N'est ce pas which serves precisely the same purpose for all interrogative tags.

So should we insist that our kids speak correct formal English or should we be more tolerant and accept that language is constantly evolving?  I'd be interested to hear others' views.