Despite a growing dependence on foreign workers, few U.S. employers offer English-language training to help bridge the language barrier for immigrant employees, a Conference Board study shows.

In a recent survey of 71 human resources managers, 66 percent said their companies don't offer English-language training, the New York-based private research firm reported.

According to the latest Census data, immigrants currently make up about 15 percent of the U.S. labor force. More than half are from Latin America and a quarter are from Asia. Only about 40 percent speak English when they arrive in the United States.

To cope, many employers are now hiring bilingual managers, the survey found. Conference Board researchers say investing in a language training program allows employers to recruit the best available talent, regardless of their language limitations.

Immigrants are projected to account for half the growth in the nation's working-age population by 2015.