How much time does it take a child to become bilingual? If we define bilingualism as enough proficiency to function adequately and comfortably in both languages, most studies suggest at least fifteen hours per week are necessary in the minority language. (This is not a outright rule--there are too many factors to control. Some researchers say twenty-five hours per week is a more realistic number.) If you are interested in using another language with your child on a more part-time basis, here are three factors that could increase your child's likelihood of becoming bilingual: