The number of pupils taking GCSE Chinese dropped by a massive 42 per cent this year after the introduction of new speaking and writing assessments triggered an exodus to the IGCSE syllabus.
Numbers taking GCSE Chinese fell from 3,650 in 2010 to 2,104 this year, figures released last week reveal.
Teachers, academics and advisers working with community groups warned last year that a change to the rules on coursework would mean a drop in numbers.
The new rules meant that for the first time pupils studying certain community languages had to undergo controlled assessment of their speaking skills by a trained teacher in an examination centre, usually in their mainstream school.
The difficulty arose because most students taking such languages study in supplementary schools during the evenings and weekends.
In the past, GCSE Chinese, along with Urdu, Arabic and Japanese, could be achieved without a speaking test, but now all languages have a compulsory speaking unit.
Less popular community languages can still be assessed through a teacher invigilating an oral examination and sending the recording for external marking. But the Qualifications and Curriculum Development Agency, which oversaw the new accreditation, said Chinese and Urdu had to be tested through controlled assessment for speaking and writing due to the number of entries.
Colin Lai, committee member of the UK Association for the Promotion of Chinese Education and headteacher of the Portsmouth Chinese School, said: "Mainstream schools do not have the resources for a controlled assessment of Chinese. They need to hire someone to do the assessment and this means there will be more expense. That is why many schools this year were not willing to enter students for GCSE."
The problems come despite regular promotion of GCSE Chinese by Government ministers, including education secretary Michael Gove, who emphasised its importance on a trip to China last year.
The move to controlled assessment is also thought to be behind the drop in the number of entries for Urdu, which fell by 21 per cent from 5,020 to 3,960.
But there has been a drop in all 19 languages taken at GCSE, apart from Modern Hebrew which rose from 433 to 445 entries.
French dropped 13 per cent over the past year to 154,221 entries. German, which was taken by 60,887 students in 2011, is down from more than 70,000 last year. Even Spanish, which has seen entries rise every year since 2005, saw a drop of 2.5 per cent this year.
Helen Myers, chair of the London branch of the Association for Language Learning, said the drop was partly due to languages being seen as harder than other subjects.
"These people opted for doing languages two years ago when there was no incentive because of the severe grading issue," she said. "There is some anecdotal evidence that things are changing with EBac."
An Ofqual spokesperson said: "Requirements for assessments are in place to ensure those assessments are fit for purpose and administered securely and appropriately. There are no immediate plans to change the languages exempt from the requirements for spoken assessments. Our wider research into the introduction of controlled assessment, which is also relevant to languages, is on-going and findings are due to be published later this year."