An overhaul of GCSE coursework has been damaging to modern foreign language classes, according to a report by the exams regulator.
It reveals teachers' concerns that the move to axe traditional coursework and replace it with "controlled assessment" has put pupils' learning at risk.
Teachers have less time to teach, and are forced to concentrate on the topics and language that students will need to use in their controlled assessment work at the expense of other areas, the Ofqual report says.
The study, based on interviews with modern foreign language (MFL) teachers, comes after a report last year raised concerns about the impact of controlled assessment on languages.
The new study reveals that most of those questioned had "significant concerns" about the new system, with some calling for a return to traditional coursework, the Press Association reported.
Controlled assessment was introduced around three years ago, amid concerns about cheating and plagiarism.
Under the new system, GCSE pupils complete coursework under strict classroom supervision, rather than doing it at home.
Ofqual's report found that most MFL teachers believe that teaching time has been reduced, and that learning has been narrowed by the new system.
"Teachers feel that they have no alternative but to concentrate their teaching on the topics and language that are part of controlled assessments at the expense of other topics, and to focus on the vocabulary and structures their students need to gain high marks in the assessments rather than teaching more broadly," the report says.
This is because the assessments are seen as "high stakes" with both teachers and students feeling pressurised into focusing on these tasks.
Some of these questioned told Ofqual that students reading and listening skills were suffering because they were focusing more on what they need to do for their controlled assessments.
It adds: "Some teachers perceive that assessments test memory rather than language skills, and this can undermine their confidence in the validity of the assessments. Teachers say that students often learn their written and oral material by rote, and simply reproduce it during the task-taking.
"Although teachers do not seem to encourage this type of learning, many feel that it is an inevitable consequence of setting and preparing assessments in advance, as students see learning pieces by rote as the means by which to prepare for the assessment and to gain the best possible marks."
The report does not draw conclusions, but Ofqual said that the findings will be part of a wider review into controlled assessments in all GCSE subjects.
It comes as a study by Cambridge Assessment found that almost half of teachers believe that the new-style coursework has cut the risk of plagiarism.
But there were concerns that the risks have not been eliminated and that there is the potential for abuse of the system by teachers and students.
The exam board's report also says that many teachers believe that controlled assessment has changed the way they teach and that the knowledge and skills gained by pupils has altered.
And it found that there are reports that students feel they are constantly being tested.
There were also concerns about how to dealing with student absences, student motivation and timetable and technology issues, it says.
The report looked at controlled assessment in six different areas - design and technology, French, geography, history, child development and PE and has been submitted to Ofqual for its review.
Mark Dawe, chief executive of OCR, which is part of Cambridge Assessment said: "Practical work is important in some subjects but not all and there is something we can learn from that.
"There are ways of encouraging that practical learning to happen without always testing the practical skills on the day under heavily controlled conditions.
"Cambridge Assessment's in-depth study supports the idea that controlled assessment is flawed but that teachers do like some form of internal assessment."