Media playback is unsupported on your device Media caption Llyr Gruffydd says on present rates it could take 800 years to ensure Welsh medium education for all

The teaching of Welsh needs to be boosted to help reach the government's target of one million Welsh speakers by 2050, Plaid Cymru has said.

The party wants more funding found to ensure more teachers and assistants can use the language in the classroom.

Shadow Education Secretary Llyr Gruffydd claimed the number of children being taught in Welsh was "flatlining".

Plaid Cymru has used a Senedd debate on Wednesday to stress the role of education in promoting the language.

First Minister Carwyn Jones announced the target of one million Welsh speakers at the National Eisteddfod in Abergavenny in August.

His minister for the Welsh language, Alun Davies, described it as "deliberately ambitious".

In its assembly election manifesto, Plaid Cymru said the aim should ultimately be Welsh-medium education for all.

'800 years'

"Over the past four years we've seen the number of pupils receiving Welsh medium education flatlining," Mr Gruffydd told BBC Wales ahead of the debate.

"I think there's been a small increase of 0.01%.

"If we want to see a situation where all children in Wales receive their education through the medium of Welsh, it will take 800 years to achieve at this current rate."

In the motion for debate, Plaid called for a "clear timetable" for a new GCSE to replace the one for Welsh as a second language.

It said a new Welsh course for all pupils should be introduced by 2018, pointing out it was three years since the idea was recommended in a report by Prof Sioned Davies of Cardiff University for the Welsh Government.

Mr Davies told AMs that education in Wales was being reformed, saying that from 2021 the new curriculum would remove the distinction between Welsh and Welsh as a second language.

Suzy Davies, Welsh Conservative spokeswoman on the Welsh language, said there should be more focus on Welsh "outside the classroom", saying: "This is where the language really lives.

"By including small bits of Welsh into everyday life, we can help grow the language from a grassroots level so that our pupils walk out of the school gates and into communities where they can use both their languages," she added.

Meanwhile the Welsh language commissioner has said ministers should intervene to ensure local councils respond to demand for Welsh-medium education in their areas.

Meri Huws told BBC Radio Cymru she welcomed recent developments in Cardiff, Newport and Pembrokeshire, but urged Education Secretary Kirsty Williams to look at the picture across Wales and ask if it was good enough.

Analysis by Arwyn Jones, BBC Wales political correspondent

Plaid Cymru's call that all pupils follow one Welsh GCSE qualification by 2018 would need a far greater emphasis on the subject in English-medium secondary schools.

The party says Welsh should be a core subject in all schools, not just Welsh-medium schools, as is the case now. That would mean more time on the curriculum for Welsh at the expense of other subjects such as English, maths and science.

A Welsh Government commissioned report into the teaching of Welsh as a second language raised concerns about the number and quality of teachers able to teach the subject.

Plaid Cymru wants to "invest substantially, and seriously plan, through a series of innovative initiatives, in order to quickly increase the number of education practitioners who teach through the medium of Welsh".

However, if they want a new GCSE qualification to be taught in two years' time it will be difficult to recruit and train the additional teachers needed to deliver the course.