The decline is surprising as Jersey has a history of French-speaking. Only 52 students took A-level last year. A-C grades were gained by 46.2 per cent compared with 61.9 per cent in the UK. There were just three grade As - 5.6 per cent - compared with 21.6 per cent achieving As in the UK.
David Rowles, an adviser from the Roehampton Institute, is working with heads of modern languages to review approaches to teaching and learning. There is sharp disparity between Jersey's GCSE results - well above the UK average - and disappointing A-level performances.
"We need to establish whether there is some fundamental cause. We have a higher proportion of students going on to post 16-education. It could be argued that the range of ability studying A-level is greater," said Jersey's director of education, Tom McKeon.
Aidan Smith, a keen linguist and president of Les Amities Franco-Britannique de Jersey, an Anglo-French cultural society, believes the booming finance and legal industries have played a part.
Agriculture is also no longer dependent on Breton labour, so French is spoken less among the farming community. "There needs to be massive investment in French," he said.