Switzerland's education chiefs have proposed to make it compulsory for primary school children to learn English to prepare them for the world, the Swiss news agency said.

But it said public education experts meeting in the capital Berne stressed that an upgrading of English as a second language must not be at the cost of any one of the four national tongues.The proposal may prove controversial in a linguistically diverse country where language is often seen as a key unifying element - 65 percent speak one variety or another of Swiss-German, 18 percent French, 10 percent Italian and 1 percent one of the four Romansh dialects.

Currently, English is officially taught for only one or two years before the school-leaving age of 16.

German-speaking Zurich, Switzerland's most populated canton, announced plans this year to start compulsory English at an early age.

But the issue of whether German-speaking kids should ditch French at an early age for English immediately caused an uproar in French-speaking Switzerland amid fears French will lose its strength in German-speaking areas and endanger Swiss political unity.