Language proficiency refers to the degree of an individual's ability to use a language effectively across relevant communicative contexts and linguistic tasks ^[1][2]. It encompasses multiple dimensions of competence, including listening, speaking, reading, and writing, as well as vocabulary, grammatical knowledge, and pragmatic appropriateness, depending on the assessment framework and intended use ^[1][2]. In language acquisition research and natural language processing, proficiency may be characterized through performance measures, linguistic features, or standardized assessment criteria, with the specific dimensions and thresholds determined by the context of evaluation.