A "tidal wave" of English learning that will leave half the world's population able to speak English within a decade could wipe out part of the UK's competitive advantage in the overseas higher education market.
Two billion people could be learning English by 2015, leading to some three billion speaking the language, according to the interim conclusions of a study by David Graddol, a lecturer and researcher on global English.
A report on the findings, released at the British Council's Going Global international education conference in Edinburgh this week, says the trend will mean feast followed by famine for the English-language teaching industry. Demand for English teaching will outstrip supply in the short term, but by 2050 the boom will be over as the number of English learners drops to about 500 million.
British Council officials are concerned that while more English speakers could mean a larger market for UK higher education, it may also increase competition from non-Anglophone countries.
Tony Buckby, the British Council's deputy director for English-language teaching, told The Times Higher : "Some countries may see the chance to offer courses in English in a multilingual environment as their unique selling point."
UK graduates and academics who speak only English may suffer disadvantages in the global jobs market even though more people will be able to understand them, Mr Buckby said.
Mr Graddol, a former Open University lecturer who heads an applied language studies consultancy, said: "The world is rapidly becoming multilingual, and English is only one of the languages people are learning. There is a rush towards Chinese in some parts of the world, and Arabic and Spanish are both key languages of the future."
The study is based on a computer model of language learning trends, using data on demographic projections, education and demand for courses, from the United Nations, Unesco and the British Council. A fuller analysis of the findings is due to be published by the British Council next year.
Charles Clarke, the Education Secretary, told more than 700 delegates from 59 countries at the conference that overseas students added more than £4 billion a year to the UK economy, while English-language teaching was worth about £1.3 billion. "We cannot be complacent in our drive to maintain the UK's competitive advantage on the international education market," he said.
Neil Kinnock, the British Council chairman, called for "shared directions and coherent approaches" between government departments and other key players in international education on issues such as immigration, visas, rights of residence and work permits, to make British education more competitive.