**1. Introduction**

Multilingualism alludes to both a person's capacity to utilize a few dialects and the coexistence of distinctive language communities in one geological area [1]. Besides, Edwards and Aronin [2, 3] contend that multilingualism is the phenomena of the present age; however, it has existed throughout the whole of human history. As society moves ahead, the expansion of multilingualism is attributed to the social, linguistic, and cultural changes derived from globalization, geographical, and social mobility, economic and political transformations, and the development of technology [2, 3]. Hammarberg [4] states that multilingualism is the normal condition of language ability and that humans are multilingual by nature [4].

In the book *Introducing Multilingualism*, Weber and Horner [5] refer to Blommaert's [6] definition of "multilingualism" and they state that we all have a variety of linguistic resources at our disposal and it can refer not just to one or two languages one may possess. Thus, Weber and Horner [5] do not distinguish between such terms as bilingualism and trilingual, but subsume them under one concept of "multilingualism." Multilingualism, thus, ought not to be seen as a collection of languages that a speaker control, but it may be seen as a complex semiotic asset, of which a traditional defined "language" has a place in a few, while a distinct "language" has a place in others. Among the resources are concrete accents, language

varieties, registers, styles, modalities such as writing ways of using language in certain communicative situations and spheres of life, and people's ideas about such methods of utilizing their linguistic ideologies [5, 6].

According to Blommaert [6], we are all multilingual to a certain degree since we use different "linguistic varieties, genres, registers, accents," and it does not matter if our linguistic recourses belong only to one "conventionally defined language" or several of them. He further points out language ideologies in his conception about multilingualism. He connects these ideologies with the ideas people have about the way of using languages they possess, the way they define a language and multilingualism, their beliefs about how language is used and how it works. Aronin and Singleton [7] share with Blommaert's [6] similar ideas about multilingualism. They describe it as a new social phenomenon in itself, not just adding numbers of languages to individuals and societies. They view multilingualism as a "new linguistic dispensation," which means "language ideologies and policies, language education in all its dimensions, and the patterns of language use of communities and individuals. It also encompasses the systemic development and evolving status of the full spectrum of extant and emergent language varieties" [7].

According Franceschini [8], today the term multilingualism "denotes various forms of social, institutional and individual usage as well as individual and group competence, plus various contexts of contact and involvement with more than one language." Franceschini states that the study of multilingual phenomena takes into account the practice of using more than one language, including regional languages, minority languages, migration languages, and language varieties such as dialects, to varying degrees of proficiency among individuals and societies [8]. Thus, the term "multilingualism" is being used increasingly and it refers to societies, nations, individuals, who use more than one language in everyday life, in variety of situations to varying degrees. Multilinguals then are the one who have two or three languages in their repertoire.

"Bilingualism and multilingualism are normal, unremarkable necessities of everyday life for the majority of the world's population" [9]. However, different sociolinguists use the terms "bilingualism" and "multilingualism" in different ways. For example, Romaine [10] uses these terms interchangeably to refer to the routine use of two or more languages in multilingual speech communities. In this chapter, I use the term "multilingualism" to refer to the routine use of two or more languages in a community. Sociolinguists know that multilingualism is not the aberration or minority phenomenon many speakers suppose it to be. It is, rather, a normal and unremarkable necessity for the majority of the world's population. Although it is so difficult to provide the exact statistical data on the multilingual speakers and distribution of multilingualism in the world, the focus of this chapter is to succinctly describe the sociolinguistic aspects of language choice and use of multilingual speakers in various domains. Besides, some of the relevant issues are related to language choice and use in multilingual speech communities, in different parts of the world. Furthermore, factors and recent developments for the spread of multilingualism in various parts of the world are also reviewed and included in this chapter.

### **2. Language and sociolinguistics**

Spolsky [11] affirms that, during the last 40 years or so, sociolinguistics has been acknowledged as an independent scientific study that accounts for the relationship between language and society. The field of sociolinguistics, Llamas [12] maintain, in the early twenty-first century has become a mature, definitive, and

#### *Multilingualism and Language Choice in Domains DOI: http://dx.doi.org/10.5772/intechopen.101660*

vigorous discipline. Hudson [13] on his part propounds sociolinguistics as the study of language in relation to society. Yet again, according to Coupland and Jaworski [14], sociolinguistics is defined as "the study of language in its social contexts and the study of social life through linguistics." Further, Fishman [15] uses the term sociolinguistics to embrace both the sociology of language and sociolinguistic. Multilingualism is one of the basic concepts dealt in sociolinguistics.

In sociolinguistics, no matter how it is defined, as partially already mentioned, "Language is not simply a means of communicating information. It is also a very important means of establishing and maintain relationships with other people" [16, 17]. In other words, "the fundamental sociolinguistic question is posed by the need to understand why anyone says anything" [18]. Clearly, in the field of sociolinguistics, language is the key point that links speakers to other people and to society in general. As a matter of fact, the use of language is probably what separates humans from other species and what explains the peculiar ways of living together we can call society or community [19]. That is to say, whether it is used as a basis or as the main topic, language is the essential and central instrument that brings human beings together by creating societies and communities. In [20] terms, "language is the principal means whereby we conduct our social lives. It expresses cultural reality through all its verbal and non-verbal aspects, language embodies cultural reality." In other words, language might be consider the fundamental instrument within the society in terms of communication, but also one of the main tools that convey and constitute elements of culture and values. This point, on which there seems to be no conflicting opinions, allows all sociolinguistic research to be carried out.
