Over two decades, six studies evaluated the effects of a home-based early language program on the development of 101 infants. Parents engaged in enrichment activities with their infants over a one-year period that began when the infants were between three and 13 months of age. Participants from families with varied levels of education were selected to examine the effects of enrichment in language, problem-solving or gross-motor experiences on their development. These studies investigated the use of the program by Cantonese-speaking and Italian-speaking immigrant parents, at-risk Afro-Caribbean immigrant parents and economically advantaged English-speaking parents. Positive effects were obtained on measures of language and general intellectual abilities at program termination at the end of a one-year intervention period and on school performance, interviews, Wechsler Adult Intelligence Scale-Revised, Scholastic Aptitude Test, motivational and self-esteem questionnaires administered to some participants between the ages of 15 and 22 years. (Contains 9 tables)