Muslim women who fail to improve their English language skills could be deported as part of a drive to build community integration and counter extremism, David Cameron has said.
The Prime Minister warned that not speaking the language adequately could make people "more susceptible" to the recruitment messages of groups like the self-styled Islamic State (IS) - though there was no "causal link".
And he said it was "not acceptable" that women in parts of the UK were not allowed to leave their homes without a male relative and faced sex-segregated school governors meetings.
A £20 million language fund is being set up to help end what he called the "passive tolerance" of separate communities which left many Muslim women facing discrimination and social isolation.
Women who come to the UK to join husbands will face tests after two and a half years - with failure meaning "they can't guarantee they will be able to stay" even if they have children, Mr Cameron told the BBC Radio 4 Today programme.
"You have to be able to speak a basic level of English now to come into the country as a husband or a wife.
"We have made that change already and we are now going to toughen that up so halfway through the five-year spousal settlement programme, there will be another opportunity to make sure your English is improving.
"You can't guarantee you will be able to stay if you are not improving your language.
"It is tough. But in the end it is not enough just to say the Government is going to spend more money and it is our responsibility. People coming to our country, they have responsibilities too."
He said: "I am not blaming the people who can't speak English. Some of these people have come to our country from quite patriarchal societies where perhaps the menfolk haven't wanted them to learn English, haven't wanted them to integrate.
"Where there is segregation, it is holding people back, it is not in tune with British values and it needs to go. We need to be more assertive."
The Government estimates that there are 190,000 Muslim women in England who speak little or no English.
Mr Cameron told Today: "The reason for doing this is to build a more integrated country, to build a One Nation Britain, to give people more opportunities.
"But I think there is a connection with combating extremism and it is this: if you have people growing up in a house where no-one speaks English, they are less able to talk to the school, less able to communicate with a local GP.
"I am not saying there is some sort of causal connection between not speaking English and becoming an extremist, of course not. That would be a ridiculous thing to say.
"But if you are not able to speak English, not able to integrate, you may find therefore you have challenges understanding what your identity is and therefore you could be more susceptible to the extremist message."
He defended previous cuts to language funding which critics say have undermined integration efforts.
"We had to make difficult decisions. Now what we are doing is targeting the language money much more accurately.
"It is just for women, not necessarily just for Muslim women - it is for those in the greatest danger of isolation."
And he rejected the idea of banning full-face veils as part of the policy.
"In our country people should be free to wear what they like," he said.
"When you are coming into contact either with different institutions or, for instance, you are in court or you need to see someone's face at the border then I would always back the authorities or the institutions that have put in place proper and sensible rules.
"Going for the French approach of banning an item of clothing, I do not think that's the way we do things in this country and I do not think that would help."
Writing in The Times, the Prime Minister said he would not avoid telling the "hard truths" required to confront the minority of Muslim men whose "backward attitudes" led them to exert "damaging control" over women in their families.
Mohammed Shafiq, chief executive of the Ramadhan Foundation, said: "David Cameron and his Conservative Government are once again using British Muslims as a political football to score cheap points to appear tough.
"There are three million Muslims in this country and the Prime Minister chooses to focus on a very small minority of extremists when clearly the majority of British Muslims reject extremism.
"The Ramadhan Foundation has been clear for many years that we face an increased risk from terrorism and an ideology of hatred. The best way to confront it is to build support within Muslims and support the work done across the country, and not lashing out and denigrating Muslims.
"The irony of the Prime Minister calling for more resources to help migrants learn English when his Government cut the funding for English classes in 2011 has not been lost on many people.
"This was a right-wing, neo-con Prime Minister delivering more of the same disgraceful stereotyping of British Muslims.
"Rather than focusing on the positive contribution of our faith and community, he focuses on the extreme minority of issues which clearly is not representative.
"Many in the British Muslim community will reject this neo-con agenda and continue our work in confronting extremism and terrorism without the support of the Conservative Government."
Shadow home secretary Andy Burnham said: "In his desire to grab easy headlines, David Cameron risks doing more harm than good.
"His clumsy and simplistic approach to challenging extremism is unfairly stigmatising a whole community. There is a real danger that it could end up driving further radicalisation, rather than tackling it.
"The Prime Minister is right to talk about empowering women but his emphasis should be on women of all faiths and none. His commitment to English classes is welcome but people will ask why his Government has spent the last few years cutting funding from these vital courses.
"Tackling extremism is the greatest challenge of our age. We are willing to work with the Government to get it right.
"But it is a deep-rooted and complex problem and requires a more sophisticated approach than we have seen to date and a stronger sense of partnership with the Muslim community."
Liberal Democrat leader Tim Farron said: "This announcement is dog-whistle politics at its best.
"David Cameron cut the budget for English language classes in August last year by £45 million. Now the Prime Minister is dressing up a massive cut as a £20 million funding commitment.
"Linking women in the Muslim community who struggle with the English language to home-grown extremism only serves to isolate the very people Cameron says he is trying to help.
"Liberal Democrats support English language classes for anyone regardless of race, religion or gender and blocked these plans to cut funding for them in coalition."