Media playback is unsupported on your device Media caption Only in Gwynedd and Anglesey is the Welsh language still dominant

The number of people who speak Welsh has fallen in the past 10 years, according to the 2011 census.

Figures also suggest Welsh is now a minority language in two heartlands, Carmarthenshire and Ceredigion.

It has been thought that migration trends and education might lead to an increase in speakers in less traditional Welsh-speaking areas.

But the census suggests otherwise, with just two areas, Monmouthshire and Cardiff, seeing a percentage increase.

Only in Gwynedd and Anglesey do over half the population now speak Welsh.

WELSH LANGUAGE FACTFILE 19% of the Welsh population aged over three said they were able to speak the language

Able to speak Welsh: 562,016 Not able to speak Welsh: 2,393,825

Gwynedd has the highest percentage of residents aged three or over who said they can speak, read and write in Welsh (65,900 people, 56%)

In Carmarthenshire, 43.9% of the population aged over three said they could speak Welsh in 2011, down from 50.3% in 2001 and 54.9% in 1991

In Ceredigion it was 47.3% in 2011, down from 52% in 2001

11.1% of the population of Cardiff said they could speak Welsh in 2011, a 0.1% increase

Monmouthshire also reported a slight increase in the number of Welsh speakers at 9.9% - up from 9.3% in 2001

Blaenau Gwent reported the lowest percentage of people who could speak Welsh at 7.8%.

Source: Census 2011/ONS

Census 2011: Key Welsh data

The Welsh government said it took some comfort from the fact there were considerable increases in younger children who spoke Welsh.

This is seen as a sign that efforts to promote the language amongst young families were paying off.

The number of Welsh speakers overall has fallen from 582,000 in 2001 to 562,000 last year, despite an increase in the size of the population. This represents a two percentage point drop - from 21% to 19% - in the proportion of Welsh speakers.

The percentage of the population with no Welsh language skills also increased from 2001 to 2011, according to the Office for National Statistics (ONS) data.

Speaking before the results were released, First Minister Carwyn Jones said he expected figures to show a smaller proportion of Welsh speakers in the traditional stronghold communities of the language, but with more people speaking Welsh in other parts of Wales.

However, the data suggests Cardiff and Monmouthshire are the only local authority areas to have registered a percentage increase in the proportion of Welsh speakers.

But in Cardiff there was only a slight rise, from 11% to 11.1%, and Monmouthshire reported a slightly larger increase in at 9.9%, up from 9.3%.

There are differences within age groups, with increases in the number of Welsh speakers among younger children aged three to four, a slight increase for adults 20 to 44, and decreases for other age groups.

Analysis The census is the gold standard for measuring where the Welsh language is. These figures have been collected for nearly 200 years. If we look back in history, if we go back to the late 19th Century when the majority of people in Wales spoke Welsh, a huge percentage couldn't speak English; you then have over three-quarters of a century a catastrophic decline. The last big fall was between 1961 and 1971 when it fell by 26% to 19.8%. Since then, the language has stabilised. In fact in the last Census in 2001, those who spoke it rose a tiny fraction. Today's drop then will come as a disappointment to the Welsh government and language activists. Welsh has dropped into minority status in Ceredigion and Carmarthenshire for the first time and there were big drops in the traditional northern heartlands of Gwynedd and Anglesey as well. Most of the fall in those areas can be explained by inward-migration by non-Welsh speakers. Overall 26% of the population of Wales were born outside its borders - second only to Luxembourg in European terms. The overwhelming majority on in-migrants came from England. In spite of the decline in the number of Welsh speakers the feeling of Welsh national identity appears to be growing with 66% of the population ticking the Welsh tick-box. Unsurprisingly perhaps the places with the strongest sense of Welsh identity were the south Wales valleys where the vast majority of the population was born in Wales. Betsan Powys: 2011, the year of sharp decreases

Gwynedd had the highest percentage of residents aged three and over who said they could speak, read and write in Welsh, at 56%.

It has also been suggested that parents have previously over-estimated the ability of their children to speak to Welsh.

This is because the numbers of younger adults who said they spoke the language had fallen in comparison with figures from 2001, even though many of them may have attended Welsh-speaking schools.

Pete Stokes, from ONS, said: "It could be over-estimating by parents. It could also be outward migration from Wales as people who are well-qualified are more likely to leave Wales.

"It could be that people when they leave education don't use Welsh in their day-to-day lives."

Welsh Language Commissioner Meri Huws said the findings came as a shock.

"Perhaps there has been a danger for everyone to be lulled into a false sense of security 10 years ago, believing everything would be alright, and that the growth in some areas would make up for the decrease in other areas," she said.

"If that was the case for the past 10 years, the alarm clock has rung very loudly this morning, and there are very definite challenges to be faced here, and urgently."

Earlier, First Minister Carwyn Jones said the next challenge for the Welsh language was to ensure young people spoke it outside the classroom.

Mr Jones said his own children speak English to each other, despite going to a Welsh-language school.

"Cracking that is going to be crucial to the future of the language over the next 10 years," he said.

Other politicians said action was needed to stem the decline in the language.

Plaid Cymru leader Leanne Wood AM said: "Today's figures are disappointing and I'm sure citizens across Wales will be concerned about the decline in the number of Welsh speakers across the country.

"These are very clear warning signs for the future of the language and there must be a decisive response."

Media playback is unsupported on your device Media caption A group of learners in Pontypool, Torfaen, explained why they began Welsh classes

Tory language spokesperson Suzy Davies said: "There is a generation of young people who have studied Welsh to the age of 16 at school, yet they still don't see themselves as Welsh speakers.

"How much of that is down to a slow shift in how we see ourselves? How much is down to low priority that the language has in some English-medium schools, despite being a compulsory part of the curriculum?"

Robin Farrar, chair of Cymdeithas yr Iaith Gymraeg (Welsh Language Society) said the language faced a crisis.

"This news reflects very badly on the Welsh government who set a target of increasing the number of Welsh speakers by 5% over the decade. Over the last 10 years, they have failed to support the Welsh language in the way they should.

"The fall in all the counties in the west is a matter of great concern. The people of Wales are very supportive of our unique language, but the government isn't matching their ambition."

Welsh education minister Leighton Andrews said: "The Welsh language and Welsh language communities face challenges and the issue now is not to blame people but decide how to work together to ensure a sustainable future for the language."

He said he would be open to new ideas and had a strategy, launched in March, which included encouraging the use of Welsh in social media.

A Welsh government spokesman added that the strategy recognised the "fragile state of the language" and looked to promote its use across all walks of life.

Other data from the census showed: