This paper aims at examining the reasons why laws have been introduced and put into effect mainly within Europe which require that adult migrants who apply for long-term residence permit, citizenship and family reunification, acquire both linguistic competence and basic knowledge regarding the culture and civilization of the host country. Firstly, it provides an account for these laws, discussing their substantial differences and similarities. In an attempt to understand why such laws have been enacted, this thesis sheds light upon three parameters: the official justifications for the introduction of the laws, the socio-historical context within which they have been enacted, and finally the critical approaches towards their official justification. More specifically speaking, according to the official justifications, these laws promote not only the social well-being of the host country as a whole but also the welfare of the immigrants themselves. The examination of the socio-historical context of these laws has showed that the immigration policies implemented by the European countries, some of which are the laws that this paper refers to, were affected by the steady rise of immigration from Third countries at the end of the 20th century, the phenomenon of terrorism and the social uprisings that took place. On the other hand, critical approaches towards the official certification and justification of these laws argue that such justifications usually appear to overlook and circumvent the fact that these laws aim at controlling the migration flow, selecting some immigrants over others. It is argued that this happens due to: the immigrants’ obligation to acquire the language and culture of the host country being certified through formal written assessment which sometimes proves to be highly demanding for many immigrants. The successful results of this specific assessment may be hindered by factors such as the lack of time for instruction and training, the high cost, poor knowledge of the mother tongue, the examinees’ age. Taking into consideration all the above, it is easily inferred that the most substantial goal that these laws should meet is the control of the migration flow.