Plurilingualism is an academic concept and research field concerned with an individual's dynamic and developing linguistic repertoire, encompassing the totality of languages and language varieties they know and use, and how these are integrated and deployed in communicative contexts. It investigates the interconnected nature of an individual's language knowledge and skills, emphasizing the ability to draw on different linguistic resources flexibly and strategically, thus challenging monolingual ideologies and informing understandings of language learning, use, and policy.