Young people face being overlooked for jobs because of their inability to speak English properly, education and business leaders have warned.
Street slang made popular by rap music artists and wider TV culture is making thousands of youngsters unemployable.
The Campaign for Real Education called for teachers to focus on improving pupils' use of spoken English.
The CBI said companies were having to pay to bring the language skills of some workers up to scratch. Basic grasp
Phrases such as "what g'wan", which means "how are you doing?", and "allow me a brown", which means "may I have a cigarette?", are failing to impress potential bosses.
Nick Seaton, the chairman of the Campaign for Real Education, said: "The key purpose of state education is to provide children of all backgrounds with a basic grasp of written and spoken English.
"If that is not happening then the system is failing them."
CBI spokesman Chris Clifford said employers were having to carry out "remedial training" of some staff because of their poor language skills. Speaking matters
"They are having to spend time and effort bringing people up to the level they would expect them to be at when they come out of the education system."
Company directors have also raised concerns that the increased use of email and mobile phone text messaging is affecting their employees' ability to communicate properly with customers and colleagues.
Communications consultants the Aziz Corporation said 60% of bosses surveyed believed workers were becoming fluent at email and phone text messaging at the expense of their spoken English skills.
Chairman Khalid Aziz said earlier this week: "We are witnessing a decline in the overall level of communications skills within business, and the blame for much of this lies in the way technology is being used in the workplace." BBC News