This document discusses multilingualism at both the individual and societal level. It defines multilingualism as the use of multiple languages by an individual or community. It describes types of multilingualism like individual multilingualism involving a person using more than two languages, and societal multilingualism involving linguistic diversity within a region. Key concepts discussed include language shift, where a dominant language is adopted, and language maintenance, where multiple languages continue to be used. The document also covers advantages and disadvantages of multilingualism, competence in various languages, language convergence, language ideologies, and linguistic landscapes.