Does monolingual still exist?

Monolingual means that speaker only uses one language variety. This actually rarely happens because people can acquire more than one language variety (their mother tongue and their national language, etc.).  They use their mother tongue when communicate with their family, friends or in non-formal situation, while they use their national language in formal situation such as in school, office, or when communicate with strange people. 

Moreover, in human nature, people should build relationship with others. It is very important in human life because we cannot live without interact to other. The process of interaction will make people learn other languages naturally; they become familiar with the utterance, dialect, or language varieties of the addressee. Thus interaction between other people will influence their use of language.

In building good communication and interaction, speaker should know who the addressees are. Are they older or younger people, are they our friend, are they stranger, are they our teacher, etc. When we are going to communicate to other people, we should pay attention to who we talk to, where we talk to, and what we talk to. It means that our language varieties will change depend on the speakers’ goal.

Refering to the phenomena, it means that there is practically no monolingual. Every people will use different language varieties in different occasion. The causal factors lead the user to use different language variety are migration, nationalism and federalism, education, trade, and intermarriage. In other words, mobility influences their language variety. The more they have mobility the more they have language varieties.