Which type of bilingualism is characterized by complete fluency in both languages?

Proficient bilingualism is defined by the ability to use two languages with a high level of competence and fluency in both. This type of bilingualism encompasses not just conversational skills but also the ability to engage in complex discussions, understand nuanced meanings, and utilize both languages in various contexts, such as academic, professional, and social settings.

In proficient bilingualism, individuals can switch seamlessly between languages and are often able to think and express themselves fully in both. This proficiency can include understanding and applying grammatical rules, cultural references, and vocabulary at an advanced level.

While other types of bilingualism may involve varying degrees of fluency and usage, they typically do not reach the same level of mastery that characterizes proficient bilingualism. For instance, partial bilingualism may indicate some ability in both languages but not to the same extent, while subtractive bilingualism refers to a situation where proficiency in one language declines as proficiency in another increases. Limited bilingualism suggests very basic communication skills in both languages without the depth found in proficient bilingualism.