Psychological findings on multilingualism and its effects, with special reference to educational and medical aspects: a narrative literature review

In today's interconnected world, especially in urban areas, multilingualism is a very widespread phenomenon.In this paper, multilingual is considered a person who has the ability to use more than one language in varying degrees and in different situations. According to this definition, more than half of the world's population is multilingual. People from minority or dominated groups contribute more to the spread of multilingualism than people from majority or dominant groups, so they are more frequent subjects of research on the possible impacts of multilingualism.Our goal is to briefly present the effects of multilingualism on executive functions, on developmental disorders, on development during the life cycle (childhood and old age), on certain psychological traits and dimensions (ethnocentrism, psychopathy, global personality structure), and on memory. The techniques for measuring these phenomena, the results obtained on multilinguals compared to control groups (monolinguals and patients) and the possible causes of the effects are described, pointing to some application in educational and medical/mental health contexts. Finally, some recommandations for further research are given, following by a conclusion.