Bilingualism is a multifaceted experience that researchers have examined using various questionnaires to gain insights and characterize the experience. However, there are several issues related to questionnaire choice. To address this, we applied Content Overlap Analysis to seven prevalent bilingualism questionnaires, assessing their affinity. We found little overlap in these questionnaires; most had fewer than 15% of items in common, suggesting they capture different aspects of the bilingual experience and provide complementary rather than redundant data for researchers. Our investigation highlights the importance of choosing a bilingualism assessment tool to carefully fit research questions and sample language experiences.
