**1. Introduction**

What is a logically possible answer to the logically possible question: "what is the relevance of multilingualism in a multilingual world?" This is an existentialist question and the first logical reaction will be to question whether the question is logical because it is not logically possible for multilingualism to be absent (and irrelevant) in a multilingual world (that is, in its own world). Indeed, multilingualism is at home in a multilingual world and cannot be challenged with respect to relevance. Ultimately, the real question is: what is the logic of asking multilingualism, what it is doing in a multilingual world or what "business" it has in a multilingual world? However, with such a question, we end up with a *logical "argumentum ad absurdum," a question whose answer leads to a logical conclusion of absurdity* for, indeed, it is self-evident that multilingualism owns the multilingual world, and its relevance is therefore equally self-evident. The apparently interesting question is, therefore, (on further examination) as foolish as asking a man what he is doing in his own home. Indeed, in our world of the twenty-first century, *multilingualism is the norm and monolingualism the exception* [1]. Besides, inherent *bilingualism* and *multilingualism*, over the years, language contact resulting from conquest, colonization, mass migration of populations due to disasters, and the impact of globalization has made all countries of the world multilingual in varying degrees. Given the symbiotic relationship between language, culture, and identity, multilingualism ipso facto implies multiculturalism and ethnolinguistic and ethnocultural identity have become inalienable rights. This imposes challenges for nation building, driven by ideals of ideological pluralism, social cohesion, and living together in diversity and so on, which have been the object and subject of various studies of bilingualism and multilingualism.

This chapter focuses on the compendium of aspects of recent original research contributions to more and new knowledge on *bilingualism*, and its societal corollary, *multilingualism* in the context of the knowledge economy and national development.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
