This study tackles the problem of heritage language loss or shift among immigrants' children. It is hypothesized that not only the heritage language which may shift, but the family values and sociocultural behaviours as well. The study tries to understand and further explain the process of language loss and maintenance. It drives at investigating how far the following statement true is: it is quite common among researchers and scholars that if children become fluent in L2, L1 consequently declines. The paper focuses on the Arabic language loss or attrition among the Arab immigrants' children. It begins with an introduction in order to provide the reader with a brief account to the process of language loss alongside with some definitions. In addition, it investigates the factors responsible for language loss, and simultaneously the negative consequences of this loss. Accordingly, the study attempts to explore whose responsibility the heritage language maintenance is-parents, schools, politicians, Arabic governments, or the Arab communities? Worthy to mention that the advantage of bilingualism is highly appreciated and considered in this study since it is a plus factor in this domain.