Language teachers are being told to combine language teaching with other subjects to overcome the "boring and difficult" syndrome.
New official guidance says bilingual lessons motivate teenagers, but video, photos and graphics need to be used to ensure the subject taught is not "dumbed down" to meet the level of students' skills.
The method, known as CLIL - content and language integrated learning - is used in more than 40 secondaries in England. It is thought numbers could rise further after changes to GCSE this autumn that allow schools to choose their own content, says the Languages Company, which oversees language learning for the Government.
A similar change in Germany saw the number of schools offering courses in CLIL rise from 366 schools in 1999 to 847 in 2006.
In England, the number of students learning languages has plummeted since it was made optional from age 14 in 2004.
In 2001, 78 per cent of students took a language, but by 2008 the figure had fallen to just 44 per cent.
The equivalent statistics for 2009 will be published early next year, but GCSE results released last month show a drop in entries for French of 6.6 per cent and in German of 4.2 per cent compared with 2008.
Katie Lee, assistant head and director of specialism at Willink School, a language college in Berkshire, ran a conference for 65 teachers on the subject last year.
She said: "It is not just about translating the lesson from English, but using visual aids and as many cognates (words that sound the same in both languages) as possible.
"It works because it is about meanings that matter, to use (educationist) Lord Dearing's phrase. It makes sense to talk about things they have to learn about anyway, rather than what colour their bedroom is, which is not age appropriate."
The school recently ran three history lessons about castles for Year 7 pupils conducted in French.
Ms Lee, who is also a member of the Association for Language Learning CLIL group, said: "After those lessons, one-sixth of the year group signed up for after-school CLIL classes in biology, maths and geography.
"For me, that's indicative of how they experienced CLIL. They are willing to come after school for more of it."
A conference at the Goethe Institut, London, last year attracted 80 delegates from 13 countries.
Zarife Soylucicek, of the Insitut, said: "Students who are offered CLIL perform much better compared to the performance of those students who have never been in contact with CLIL.
"If it is that simple and clear that integrated language and subject instruction enhances knowledge, we cannot close our eyes to the fact."