Exam boards must update "uninteresting and irrelevant" GCSEs in foreign languages to prevent the subject dying in schools, the exams watchdog says.
GCSE foreign language pass-rates fell last year
The Qualifications and Curriculum Authority said some topics - such as ordering food and writing to pen-friends - were uninspiring.
Languages will no longer be compulsory from ages 14 to 16 in England from this autumn.
The QCA said boards had to set "less prescriptive" tasks to raise take-up.
But Bene't Steinberg, spokesman for the OCR board, said: "We have come such a long way in the last few years in making language GCSEs more relevant that they have changed out of all recognition.
"What most people want is the ability to go abroad and be able to converse.
"We have to strike a balance between relevance and rigour. We can make it so topical that we get accused of dumbing down, or make it so tough that we drive people away.
"We want more people to take up languages, so we have to get the proper balance."
The proportion of candidates achieving grade C or above in French last year fell by 2.4 percentage points.
For German, it was 2.8 percentage points lower and 1.6 for Spanish.
From September, foreign languages will no longer be compulsory from ages 14 to 16.
Instead, there will be an "entitlement" for pupils, should they wish to study them.
However, the QCA said 35% of schools were already presenting the subjects as optional.
The QCA held seminars with around 100 teachers.
In four of the schools covered, more than half the pupils at ages 14 to 16 had stopped learning a foreign language.
The QCA report says: "A few teachers criticised the GCSE specifications for being uninteresting and often irrelevant to pupils, despite the attempts by QCA to persuade awarding bodies to include topics that are relevant to candidates and reflect their maturity, and to set less prescriptive tasks.
At GCSE, 20% of total marks for foreign languages are now awarded for "knowledge and accurate application of prescribed grammar and structures".
Dictionaries are no longer permitted in examinations.
Some teachers told the QCA that candidates might feel they were "disadvantaged" compared with those in previous years.
The report says: "They feared that this would add difficulty to a subject already perceived as more demanding than other subjects (with the possible
exception of mathematics)."
The QCA is running a pilot scheme in 60 schools with the Edexcel board, involving "more relevant and interesting topics", such as business vocabulary and the media.
An Edexcel spokesman said: "So far, it has gone well and there seems to be an improved take-up rate."
The OCR, meanwhile, is setting up a Language Ladder, starting at primary school, to assess children's skills in reading, writing, listening and speaking. It is hoped this will lead to greater interest when the children reach the age of 14.