It is often described as the "language of heaven".
But now a little primary school set in a picturesque valley is playing a vital role in trying to ensure that the Welsh language thrives for at least another generation.
Ysgol Glan Conwy, in Colwyn Bay, is the only school in Wales piloting Welsh immersion lessons for Year 2 and 3 pupils.
It claims the project has proven remarkably popular among parents in a village where, for most of the population, English is the first language.
So far 10 parents have signed up for language sessions of their own, on a course involving Coleg Harlech and the Workers' Educational Association that was launched locally this week.
Their weekly lessons start after they have dropped their children off at the school, and run in tandem with the youngsters' classes.
The immersion pilot at the 125-pupil school has been running since September, following consultation with parents. Teachers have noticed how much easier pupils find learning through Welsh as they play caffi and ask for their bara menyn (bread and butter) or paned o de (cup of tea).
Headteacher Sheelagh Thomas Hughes said: "It's important children are able to converse in both languages. The earlier they are introduced to anything the better.
"It was quite a privilege for the school and the children to be asked to take part in the first place. They feel important."
Mrs Thomas Hughes said the abolition of national tests for seven-year-olds in 2002 had given teachers the space to teach more Welsh.
"We did a lot of Welsh before Sats. But once they were introduced I had to ensure the children had the best education in the language they were best at," she explained. "If children didn't get the proper results the parents would vote with their feet."
The school now hopes to reverse a decline in the number of Welsh speakers and has a dozen pupils involved in the pilot.
Eifiona Price Williams, Y2 and 3 teacher, said: "The whole ethos of the class is Welsh. At the moment we are trying to get pupils to speak more Welsh through role-playing and dialogue. We are also encouraging social skills."
Estyn inspectors have been monitoring progress and the pilot is being watched keenly across Wales.
Delyth Roberts, the project director with the Welsh Language Board, said:
"Within the first term they get most education through the medium of Welsh, and the early feedback is very positive.
"It's a way of giving pupils a second chance. These are children who didn't choose a Welsh-medium education when they started school. The project is attracting great interest."
The Welsh Assembly announced in March last year that it wanted to give pupils the chance to enter Welsh-medium provision at different points during their school careers, instead of only at age three or five.
The go-ahead was given for pilot projects that would allow primary pupils to be immersed in Welsh so they could move into the Welsh-medium sector or study more subjects using the language.
Education and lifelong learning minister Jane Davidson said at the time:
"We are working to make bilingualism a reality."
A second round of pilots involving Y6 pupils is expected in the summer term, as children prepare for the move to secondary school.