Language is culture; it is a primary means of establishing identity with others. When the Europeans colonized Africa, for instance, they brought their French or English or Dutch culture with them and established this culture in the colonies that they formed by importing their form of government, protocol, etc. Immediately, the official language of the African colonies became the European tongue, first, because it was the language of the conqueror, but also because the African languages were not written languages.
Whenever Napoleon Bonaparte conquered a country, the first actions that he enacted were the complete control of the media in the form of the newspapers, and the establishment of French as the official language. He mandated that French be taught in the schools; French literature was also introduced into the colony.
The poet-philosopher Johann Wolfgang von Goethe stated that when one learns another language, one acquires another soul. Certainly, the colonial powers sought to condition and educate those they had conquered through the power of government and the thinking of a new language.