Language is essential as it engineers our thought, without language then, the existence of human being would be in disarray, absence of communication will render us useless or ineffective as the tiler of the world. It also distinct us from other animals; although, some animals possess human attributes as they can walk, crawl, see, sleep etc. But the only distinct is that we can communicate effectively, disseminate information across to group of people at a time. Without language our thought will be meaningless as there won't be means of conveying it out. Communication is the key.
Dementia of two languages
Meaning that, having two languages is equal to say, having two thoughts. African is a victim, can we really call ourselves African, I believe language is embedded in culture, its also an identity, so, if our language should go into extinction then, we never amount to anything in reality. Moreover, having two languages will not only confused someone but also restrain someone from communicating effectively as such person is bound to switch from one language to another which will result in clash of language and of culture simultaneously or rather lost in thoughts. As the mind would be preoccupied what to say, how to say it, whether it will be meaningful or sound perfect to the hearer, all these questions will come at once to the speaker, which won't only caused confusion but also hinder the speaker listener effective communicaton. 
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language acquisition and language learning
Language acquisition could be trace to the natural and innate ability for the child to acquire language of his community not necessarily language of his parents in a situation whereby the parents relocated to another community before or immediately after the birth of the child. While language learning is equally a language one adopted maybe, through interest or nationalisms
's preference ( language of colonial masters) in case of African society, using Nigeria as a case study, English is the language we adopted as our national language maybe, due to various ethnics groups with different language and background. To be frank, that is not really the case. whereas, we already had a language which is our mother's tongue.
Subsequently, there is always a big difference between in language you learn and the one acquired. Which is why an average African man faces alot of challenges when talking or communicating his idea to the hearer or listener. There are things, subject, value embedded in individual African culture that couldn't be expressed in English or other European languages till tomorrow. Talking about difference in alphabet, tense and language structure, even more and often, an average African man is confronted with the problems of * thinking with his mother tongue but will have to write or talk in 'English' that he learned in the four wall of the classroom alone. is that
not enough to be made a national language? but do we really have options? If African decided not to write or communicate in foreign language, are we going to survive?
Morever, reading an African book 'novel, poem, fiction, folktales' etc there are some words that would be in italic, maybe the writer couldn't find the appropriate or perfect substitute in European languages used or choice as the case maybe.
It is not that, there is going to be a change to this issues or confrontation. But African writing in English or other European languages should be given more credit compared to their contemporary most especially the native speakers who I believe have all it takes to learn and possibly development if he or she wanted to.
While Africans are busy learning European languages, the European are busy developing.
The twist in human fate. The plight of Africans in choice of languages