In this contemporary era, most of the people are willing become bilingual or multilingual. Moreover, they pursue to obtain this skill because they believe it may be definitely useful in their lifetime. Wherever people travelled to international countries due to their own purposes, where they have to speak new another nation's mother tongue. However, some of them declare it may be cause in a detrimental way, especially, socially and practically in their daily lives. This essay will focus on this statement and eventually I will explain my opinion too.