However, it is only open to primary, secondary and further education teachers and lecturers who want a “confidence-boosting” refresher course in their native language.

An Assembly spokesman said the first course was designed for those teachers who could speak Welsh “fairly fluently”. Those eligible face a tough selection process in a scrap for just 32 places.

Half of the cohort will be taught in Bangor and the rest in Cardiff.

Organisers hope to roll out to non-Welsh-speakers in the future, but it will depend on the success of the first cohorts.

Four other pilot courses will be held over the next two years.

Refresher follow-up courses for those taking part are also proposed, although the plans have not yet been fully thrashed out.

The Assembly has set aside pound;2 million per year for the pilot sabbaticals, designed to encourage bilingualism in Welsh classrooms.

But the scheme has been criticised by some heads, who say the three-month courses will cause severe staffing problems and lower teaching standards.

It is believed supply costs alone for a teacher to be away from the classroom will be around pound;7,000. But the Assembly government has pledged to reimburse the applicant’s school, college or employer for all such costs.

Canolfan Bedwyr was established in 1996 and aims to extend the use of the Welsh language among working professionals in Wales through training courses and research.

It is famed for its part in setting up the first Welsh spell-checker for Microsoft computer programmes world-wide.

The 2001 census recorded a rise in Welsh speakers, from 19 to nearly 21 per cent of the population. The biggest increase was among young people of school age.

The closing date for applications is October 21. Application forms are being sent direct to schools