In the autumn of 1934, a young graduate in French from Cardiff University found herself unemployed and penniless. But luck was on her side. Turning to the university employment office, she heard that Lycee Pasteur, in the Rhone Valley, needed an English assistant because the previous one, an American girl, had fled within days proclaiming that “no civilised person could be expected to work in those conditions”.

Within a fortnight, Eileen Coleman was in Besancon. “The post wasn’t paid: once a month I’d to go to the police station to sign a statement that I wasn’t earning. But I received board and lodging in return,” she recalls.

“My room was on the top floor of a 200-year-old convent. Furniture was simple, with an ewer, basin and slop pail. The girls slept in dormitories with washbasins and lavatories. The building was on the river. In winter when the Doubs overflowed, flooding our cellars, the rats used to come upstairs.”

Her role was to be available in a particular room at certain times to speak English to any pupils who turned up. “That was it. The teachers simply taught: discipline wasn’t their responsibility, and they’d wander quietly through absolute bedlam,” says Eileen, who on her return became a French teacher in Yorkshire.

The path to her extraordinary year was laid 100 years ago when 58 young Englishmen and women, and in the other direction 14 French youths, crossed the Channel as pioneers in a language exchange scheme. Their respective countries had become concerned at the quality of modern language teaching in their schools, and when the French government proposed an exchange of young language assistants, the UK, soon followed by Prussia, eagerly agreed.

The idea was to expose learners to a more authentic use of the language they were studying by engaging them in direct classroom conversation. Just as they do today, pupils responded better to the real McCoy than a teacher who has acquired the language academically.

“An authentic native speaker is a worthwhile resource - dynamic, lively and closer in age to the school’s children,” says Joan Hoggans, head of the foreign language assistants programme at the British Council. “FLAs receive Pounds 6,240 for 12 hours a week over eight months, so they have to be worth the school’s while.”

In 1905, the Board of Education noted: “English teachers have reported that they have greatly benefited... under conditions that bring them in close touch with the life and thought of the people and more than one headmaster in this country has expressed himself as satisfied that his pupils have much improved in their command of French as the result of these conversation classes.”

In this centenary year, French remains the dominant language with France sending 1,451 assistants in exchange for 960 UK assistants. Twenty-one countries participate, with Japan the most recent.

The advantages can be more than linguistic. In his year in Argentina, science graduate Tom Bradley, 25, was invited to contribute to an exhibition celebrating the 50th anniversary of the discovery of DNA by James Watson and Francis Crick. “Because of my science background, I was asked to help bring the exhibition alive to children. I’d show them around, do a quiz on DNA extraction and try to get them excited about genetics,” he says.

Tom even got to meet his idol, 2002 Nobel prizewinner Sir John Sulston (for physiology or medicine, shared with Sydney Brenner and Robert Horvitz).“It was an unexpected moment I’ll cherish.”

Last year, 2,699 foreign language assistants were welcomed to the UK, fewer than the 4,578 who came at the peak in 1974 when economic pressure began to have an effect. ELAs peaked in 1984, at 2,555 where it has remained roughly constant despite the decline in the number of students studying languages.

This year, 149 FLAs have joined primary schools in England through the British Council language assistants programme in which assistants can be shared by up to three schools. They will aid the introduction of language learning to seven to 11-year-olds - which the Government says must happen in every primary by 2010.

The local authority in Salford has 16 assistants working at 50 of its 84 primary schools. “It’s early days yet but anecdotal feedback suggests a high level of satisfaction,” says Peter McNamara, Salford’s school improvement officer.

For the first time, foreign language assistants in primary schools are being offered a two-day Department of Education and Skills-funded tailored training course.

The year away can be life-changing in more ways than one. Marriages aren’t uncommon and there are even dynasties.

Thirty-four years after Eileen Coleman went to Besancon, her son Jim, now an Open University professor of language learning and teaching, followed in her footsteps to assist at a lycee there. His sister Jill, and wife Anne, are former English language assistants, and his daughter Katie hopes to become one soon.

“It was a chance to be someone different, to broaden my mind,” he recalls.

“A year working abroad shows an individual can operate effectively in different linguistic and cultural contexts. A lot go on to teach, but whatever you do, you become international in a way you never can be unless you’ve immersed yourself in another culture.”

For a free information booklet andor centenary brochure, email: assistants@britishcouncil.org, or tel: 020 7389 4596; www.languageassistant.co.uk. A centenary celebration will be held on December 5 at the HSBC headquarters in Canary Wharf, London. Speakers include French ambassador Gerard Errera, German ambassador Thomas Matussek, and national director for languages, Lid King. By invitation only.