"Plurilingualism" is a term used to discuss situations in which a person has communicative abilities in more than one language. In contrast, a multilingual area might have multiple languages that are used, but individual speakers may still be monolingual. While a person may be said to be plurilingual, this distinction between the two terms makes the most sense when discussing locations and speaker communities. Colloquially, people do use the term "multilingual" to address the idea of speaking more than language, but "plurilingual" is usually considered a more precise term.
In general, most people see plurilingualism to be more appealing than multilingualism. When speakers of different languages can communicate, they are often more likely to interact and form a strong society together. Linguistic divisions can be very powerful and can make people inclined to remain in highly isolated cultural groups even when living in close proximity. Encouraging linguistic exchange between different cultural groups can ease tense intercultural relations.
The way in which plurilingual contexts develop varies, but usually involves contact between more than one culture. In some cases, however, bilingualism may be standard for an area and the bilingual community may have its own distinct culture. Linguistic competence is usually accompanied by cultural competence, because effective communication involves more than just words. This is sometimes called pluricultural competence.
Many people believe that plurilingualism is increasing because of increased exposure to multiple languages both through school and societal changes. It is extremely common for people to have at least some degree of competency in foreign languages, and plurilingualism is increasingly the norm in societies. This reflects not only increased pluriculturalism, but also a willingness to accept multiple cultures as members of a nation.
One interesting aspect of plurilingualism is that it does not require full competency in more than one language. An area in which people speak small amounts of foreign languages could be said to be plurilingual. For example, in areas near international borders, people often learn the language of their country and achieve some degree of fluency in the nearby language. Practical conversation in these contexts may not require more than basic vocabulary and sentence structures.
Arguments against plurilingualism often focus on problems with limited competency, not with fully bilingual citizens. People who do not achieve fluency in the national language of the area where they live are often accused of being unpatriotic. For some people, living in a plurilingual society is itself unpatriotic, resulting in an unwillingness to provide services in other languages. This sometimes results in very tense relations between cultures that can be passed down through generations.