A head teachers' leader says British industry fails to signal to teenagers the importance of language learning.
Fewer and fewer students are learning German
John Dunford of the Association of School and College Leaders spoke out as GCSE results showed a further decline in the entries for French and German.
The Institute of Directors said this was as misguided as it would be to credit employer demand with a surge in the popularity of religious studies.
Studying a modern foreign language is now optional beyond the age of 14.
Exam entries in French fell 8.2% from last year to 216,718 and in German were down 10.2% to just 81,000.
These were "significant" falls, said the head of the AQA exam board, Dr Mike Cresswell.
He told journalists at a briefing by the Joint Council for Qualifications that youngsters and their parents were very attuned these days to shifts in the job market, in terms of their subject options.
"I don't think there are signals coming from the employment market that doing languages will be useful."
Greg Watson of the OCR board felt the same.
"There does seem to be a mismatch between what I hear when I talk to employers about this," he said.
"They say, 'We are desperate for language skills, we are doing more business abroad'.
"When I ask if they are putting it in job adverts or a salary premium the answer tends to be 'No'."
Later Dr Dunford of the head teachers' association predicted that this year would be the bottom of the decline, as people recognised that they were doing themselves no favours in the job market by cutting out foreign languages.
He said various factors were involved, including the relative difficulty of language subjects - whose exam grades needed to be brought into line with other subjects.
Also the tourist industry in other countries was so well geared to catering for English speakers that youngsters going on holiday felt they need not bother.
But "part of what is wrong with British industry" was "the culpability of employers in failing to make it clear to young people that modern languages are important", he said.
The National Centre for Languages (Cilt) said there were no quick fixes.
As a result of real concerns, highlighted in Lord Dearing's languages review, new initiatives were in train to arrest the decline and motivate pupils.
Cilt's chief executive, Isabella Moore said: "A more diversified language offer within the new 14-19 curriculum, which stimulates students' interests and is more responsive to individual and employers' needs, is within reach but will take time to achieve."
Schools Minister Jim Knight said: "Our long-term, radical measures will increase the number of people studying languages at GCSE, A-level and beyond".
These include making languages compulsory in primary schools.
The director general of the Institute of Directors (IoD), Miles Templeman, said that seeking to pin a decline in GCSE language entries on employers was misguided.
"Presumably employer demand is also responsible for this year's rises in religious studies and physical education entries," he said.
Students made the choices, with teachers and parents, to reflect their own interests and abilities as well as employment prospects.
"Equally clear is the fact that the government is right to focus efforts on primary education and on fostering a love of languages among young children.
"For older pupils, it should also explore approaches to teaching a range of languages at a lighter, conversational level, for example by following the IoD's suggestion for a GCSE in several languages."
Other shifts in popularity in the GCSEs highlighted by the Joint Council for Qualifications included a revival of sciences, following changes to the curriculum.
Figures showed that about 57,000 youngsters had taken the new science qualification after only one year rather than two - in Year 10 of their schooling.
There were mixed fortunes for another subject which, like languages, is no longer compulsory beyond the age of 14 in England: information and communication technology (ICT).
GCSE entries fell 9.1% to 99,656 and the Applied GCSE double award suffered a 37% decline.
The change was described as "really quite interesting" by Dr Cresswell - given that, last year, entries had "shot up". It was too early to discern a trend.
The managing director of the Edexcel exam board, Jerry Jarvis, said there had been a considerable migration to some of the newer vocational qualifications such as his board's diploma in digital applications (Dida) and OCR Nationals.
He said this was because students felt they were "more relevant".
But also schools know that they can be worth the equivalent of up to four good GCSEs in the school league tables.
Edexcel says it had approximately 200,000 Dida entries in 2007 with more than 138,000 certificated completions, with other students taking BTec Firsts, also worth four GCSEs.
But these are not reported with the GCSE results. Edexcel has called for a "national vocational results day".
The boom in religious studies mentioned by the IoD saw another 7.2% rise in entries this year, to 171,123 - putting it in 10th place overall.
The top 10 subjects, driven largely by curriculum demands, were unchanged except that French and history swapped places in the middle of the table - though history also suffered a decline.
As a percentage, the biggest rise was a huge 199% in additional maths, albeit to only 9,793 entries in total.
Statistics as a subject was up 21% to 82,682, and media studies up 15.5% to 66,425.