The number of British children taking foreign language classes has nearly halved since 2000, a BBC analysis showed on Wednesday, with those learning French and German down nearly two-thirds.
The study was published with the island nation preparing for withdrawal from the European Union after 46 years of membership, an isolationist turn chosen by voters in June 2016.
The BBC polled students who take standard General Certificate of Secondary Education (GCSE) courses, which culminate in exams around the age of 16.
The total number taking foreign language classes was down 45 percent, said the study.
German was down the most at 67 percent and French fell 63 percent but Spanish was up 75 percent.
The BBC said most schools attributed the drop to the perception of languages as a difficult subject.
Shrinking class sizes have led some schools to shut down courses in order to meet strict budgets, the BBC said.
"If we have classes of 25 in other subjects, it's really hard to justify small classes in other subjects," Mike Hill, a principal of a school near Liverpool, was quoted as saying.
The study's results alarmed UK executives, with the Confederation of British Industry (CBI) big business lobby calling on the government to step in.
"The decline in language learning in schools must be reversed, or else the UK will be less competitive globally and young people less prepared for the modern world," Matthew Fell, CBI's UK policy director, told the BBC.