This paper describes some aspects of the mutual impact of languages in a bilingual situation where one language is dominant and the other subordinate. The influence of the two languages on each other is effected through the user, namely, the bilingual. When the bilingual is in the process of learning the second language, his mother tongue influences his mastery of the former, resulting in the process that has been variously referred to as mother tongue interference, approximation, or interlanguage. However, the influence does not take place in one direction only; in other words, it is not only a case of the mother tongue influencing the second language. If the second language is a dominant language its impact on the bilingual's first language can have far reaching implications.