A £20m fund to teach Muslim women in the UK to speak English will tackle segregation and help them resist the lure of extremism, David Cameron says.
While there was no “causal connection” between poor English and extremism, language lessons would make communities “more resilient”, Mr Cameron said.
But some Muslims have accused him of wrongly “conflating” the two issues.
The PM also suggested failing to learn English could affect people on spousal visas who wanted to settle in the UK.
The government says 22% of Muslim women living in England speak little or no English – a factor it argues is contributing to their isolation.
Segregation, the prime minister says, is allowing “appalling practices” such as female genital mutilation and forced marriage to exist, and increasing vulnerability to recruitment by so-called Islamic State – also known as Daesh.
He is also announcing a review of the role of Britain’s religious councils, including Sharia courts, in an effort to confront men who exert “damaging control over their wives, sisters and daughters”.