The number of teenagers taking GCSE languages has fallen sharply, leading to concerns over their future.
UK entries in French this summer were down 14.4% from 2004 to 272,140, while those for German exams decreased by 13.7% to 105,288.
GCSE languages are not compulsory in England and Wales.
The Joint Council for Qualifications said the figures raised "serious concerns" about the future, with a potential fall in qualified teachers.
'Fewer going on'
The number of entries for GCSE Spanish also fell slightly this year to 62,456 from 64,078.
JCQ director Ellie Johnson Searle said: "This raises serious concerns. If we have fewer people taking modern foreign languages at GCSE level, fewer will go on to take A-levels.
"We need to look at how many people are going on to degree courses and then going on to train as teachers."
Overall entries for languages have been declining steadily in recent years.
Since last September they have not been compulsory for GCSE students in England.
Instead, the government has set a target of all primary school pupils in England getting a chance to study a foreign language by 2010.
This, it is hoped, will enthuse children and eventually improve GCSE entries.
John Dunford, general secretary of the Secondary Heads Association, said: "GCSE entries for modern languages in 2006 will be even worse.
"Numbers are in free fall and we shall lose a generation of linguists in the nine years between now and the time when pupils learning languages in primary schools take their GCSEs.
"The government needs to carry out an urgent review of its languages policy."
David Hart, general secretary of the National Association of Head Teachers, said: "The collapse in modern foreign languages is a catastrophe.
"The government must reverse its policy which permits students to opt out at 14, otherwise there will be a crisis in state school language teaching.
"What is the use of requiring all primary children to study a language by 2010 if they can then drop it at 14?"
But a Department for Education and Skills spokesman said: "We need to be realistic about what will make language learning flourish in our schools.
"Forcing 14 to16-year-olds to learn a language won't achieve that. What we need to do, and what we are doing, is getting children involved in learning languages at a much younger age."
Languages are not compulsory at GCSE in Wales (or Scotland at the equivalent level).
In Northern Ireland, schools have to teach languages to age 16. However, they can already "opt out" of this requirement, and around half have so far.
From 2008, GCSE languages will be non-compulsory across the board, as in the rest of the UK.
Of the students taking French this year, 60.3% got A* to C grades, up from 53.7% in 2004.
For German, it was 66.6%, from 59.6%.
Across the UK, the number of overall science entries was also down this year.
Those for the double award - the equivalent of two GCSEs and taken by most pupils - fell by 32,567 to 494,450.
This was offset slightly, however, by rises in entries for individual physics, chemistry and biology GCSEs and those in single award science - up in total by 22,753.
And entries for the Intermediate GNVQ in science rose more than 4,000 or 58% to 10,995.
This year's greatest riser among the "big" subjects - those with more than 100,000 entries, was physical education, up 7.5% to 144,194.
Dr Johnson Searle said much of this could be traced to government initiatives to improve children's fitness through exercise.
The next largest increase was for religious studies, which has been rising steadily in recent years and increased by 4.6% to 147,516.
This was the subject which saw the biggest percentage rise in popularity at A-level this summer.
The "top 10" subjects, in terms of entries, all stayed the same this year.
Maths and English had the most entries.