Radical plans to increase the number of Welsh-medium schools and Welsh-speaking teachers have been revealed by the Assembly government.
Every trainee primary teacher would have to learn some Welsh and there could be more Welsh lessons in English-medium schools under the far- reaching proposals outlined in a 120-page draft strategy.
The plans, which will be consulted on this summer, could also lead to more bilingual qualifications and the scrapping of the unpopular second language short Welsh GCSE course.
Launching the strategy, Jane Hutt, the education minister, said Welsh- medium provision across Wales needed more consistency as it was "too patchy".
But reactions to the plans, which include delivery targets for local authorities and schools, were mixed.
UCAC, the Welsh-language education union, was delighted.
Bethan Guilfoyle, head of English-medium Treorchy Comprehensive, which has been praised for its bilingual approach, also welcomed the plans, but warned: "Each school has to judge the best way forward for them. It's not necessarily the best approach for all."
Critics also said the strategy could prove costly and unfair to schools and teachers who did not share the government's vision of a "truly bilingual Wales".
Dr Philip Dixon, director of the ATL Cymru union, said the strategy was a huge "wish list". "My immediate question is where are the resources going to be found when budgets are already stretched?"
Mal Davies, head of Willows High in Cardiff, said: "The strategy could put enormous pressure on schools like mine. We find it really tough to recruit good second language Welsh teachers."
Some heads and second language Welsh teachers in Anglicised areas have also questioned why Welsh is compulsory for 15-year-olds when it is such an unpopular subject.
David Marshall, head of Fairwater High in Cwmbran, said English-medium schools found it difficult to motivate pupils who have no interest in learning Welsh.
Under the proposals, local authorities would be expected to measure accurately the demand for Welsh-medium education and reorganise schools accordingly.
The draft document says there is a "potential need to increase significantly the number of Welsh-medium schools." At present, there are 464 Welsh-medium primaries and 54 secondaries.
Each authority would be expected to set up Welsh-medium education forums and make the language a priority when drawing up their education policies.
The Assembly government wants a quarter of seven-year-olds to be taught in Welsh by 2015.
It also calls for a 3 percentage point increase in the number of Year 9s assessed in Welsh first language and a rise in the number of Welsh-medium GCSE entries.
Under the proposals, there would be more Welsh-medium qualifications and more examiners who can speak the language.
Rebecca Williams, policy officer at UCAC, said many of the strategy's aims could be achieved without "substantial resources".
Top education civil servant David Hawker, said bilingualism would be expensive, but any investment would pay off with improved academic and vocational results in the long run.
But standards in Welsh continue to come under fire. Dr Bill Maxwell, Wales's chief inspector, said in his annual report that Welsh second language teaching was "much worse" than other subjects.
If the proposals are approved, they will start during 2010-11.