The present study aimed at identifying the effects of foreign language teaching on mother tongue in light of literature in the field. It followed the descriptive inductive research method by reviewing the results of the previous studies, either those which confirmed the presence of language effects on children who learn one language or two languages together or the studies which proved the opposite. This required reviewing literature on foreign language effects on mother tongue. Among the most important results of the present study were: teaching foreign languages did not negatively affect mother tongue, and teaching foreign languages did not negatively affect other aspects pertaining to the society and its characteristics such as identity and religious affiliation. Rather, the interest in foreign languages and learning them is essential for keeping pace with the scientific progress and recent developments in civilization.