In many countries, people use their mother tongue in local business, but use the language of the former colonizer in national business. How much weight should be placed on teaching one’s mother tongue and the lingua franca is a critical issue in these countries. This paper develops a model to examine these issues theoretically. It is shown that balanced education of the two languages is critical for skill development of those with limited wealth. It is also found that balanced bilingual education yields higher earnings net of educational expenditure than lingua-franca-only education only when a country has favorable educational and technological conditions (productivity is reasonably high and education is reasonably effective) and only for those with adequate wealth. Policy implications of the results are also discussed.