This study validates the Contextual and Individual Linguistic Diversity Questionnaire (CILD-Q) for measuring contextual linguistic diversity in Singapore. The work addresses the need for instruments that can capture language experience in highly multilingual environments, where language exposure and use vary across social settings, communities, and individual histories. By evaluating the CILD-Q in the Singapore context, the study supports more precise measurement of linguistic diversity for research on multilingualism, cognition, education, and social communication.