The self-reported Language and Social Background Questionnaire (LSBQ) measures an individual's language proficiency and usage quantitatively. This cross-sectional study aims to evaluate the psychometric properties of the LSBQ in the Persian (Farsi) language. A total of 325 adults aged between 15 and 59 years (mean age = 21.00 years, SD = 3.56; 251 females, 70 males) from Tabriz and Tehran participated in this study. To evaluate the Language and Social Background Questionnaire (LSBQ), exploratory factor analysis (EFA) was employed. The psychometric properties of the Persian LSBQ were assessed through various validity measures, as well as reliability analysis and receiver operating characteristic (ROC) curve analysis. The overall content validity ratio for the questionnaire was 0.98, with an impact score of 4.47. The internal consistency of the scale was satisfactory, with a Cronbach's alpha of 0.707. The EFA identified five key factors: "dominant language at home and community," "non-Persian use," "non-Persian proficiency," "Persian comprehension," and "switching". Using Youden's J criterion, an optimal cut-off points of - 1.00 was determined to effectively distinguish between monolinguals and non-monolinguals. To assess the convergent and discriminant validity of the instrument, Spearman's correlation was utilized to analyze the relationships among the variables. The Persian version of the LSBQ is a reliable and valid tool for assessing language proficiency and usage among Persian-speaking participants. It effectively distinguishes between monolingual and non-monolingual individuals. Researchers and clinicians can utilize the LSBQ effectively, provided it aligns with their specific research questions and the language experiences of their target population.
Keywords: Bilingualism; LSBQ; Language and social background questionnaire; Multilingualism; Psychometric.
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