A study estimated the size of the population of adults and out-of-school youth with limited English proficiency (LEP) who need vocational education and related employment services and projected the size of this population from the time of the study to the year 2000. Research procedures included a literature review, an analysis of 1980 U.S. census data, and projections of the population. Two measures, constructed from census data to assist in the analysis, were used to categorize individuals as either limited English-proficient or as English-proficient and also to categorize them by poverty status. The following are among the findings reported: (1) the flow of immigrants has grown steadily since 1965 until now it is almost as high as it was in the 1900s, with the most recent immigrants being less educated and skilled than those who entered 15-20 years ago; (2) the number of persons with LEP aged 16-64 was estimated to be 6.8 million in 1980, which is about 4 percent of the U.S. population; (3) their number is projected to be 11.6 million by 1990 and about 17.4 million by 2000; (4) a projected 5.5 million could require services in 1990 and 8 million could need them by 2000; (5) over half of the adults with LEP speak Spanish; (6) the likelihood of becoming proficient in English is highest within 10 years after arriving in the United States; and (7) over 70 percent of the adults with LEP living below the poverty level in 2000 will be Hispanics. (The document contains 59 tables and 46 references.) (CML)