Multilingualism, in very general terms, can be defined as the use and acquisition of three or more languages. It is the social and individual language practice that has come to the forefront in today’s human society. Its various aspects relate to spheres as diverse as human physiology, cognition, communities with their traditions and material objects, and, of course, languages. Multilingualism concerns education, engineering and commerce, policymaking, family life, and entertainment, to name only some of its dimensions. The field of multilingualism studies the way various languages are acquired, used, and treated today.

It is hard to imagine an aspect of modern life unaffected by multilingualism. The majority of the world’s population is bi- and multilingual, and those who are not, are still influenced by the mostly multilingual world they live in. Multilingualism is not about languages as such; rather it is about how people use multiple languages. Researchers study how, by whom, and in what conditions languages are acquired, spoken, and dealt with; how many and which language varieties are used or not used and why, and what are the implications of this on individuals and society as a whole.

Multilingualism has a bearing on all of us, as we have to contend with it through all the stages of life while acquiring language, pursuing a career, socializing, and getting older, as we live out our lives in the roles of language speakers, family members, citizens, and professionals. Researchers of multilingualism examine the way various languages are acquired, used, and treated today and discuss questions that arise daily in all parts of the world. For example, what is an optimal age to start teaching English as a third language? Which kinds of schools – monolingual, bilingual, or multilingual are appropriate for urban centers? Is it normal that grandchildren and grandparents do not understand each other because they speak different languages? Are there more and less economically beneficial languages? How are languages selected for work and international meetings? Why is everyone not a polyglot as Cardinal Mezzofanti was?