This article reports on the development and validation of the Informal Second Language Engagement questionnaire (ISLE) for capturing various aspects of learner engagement with informal second language practices. Whereas other questionnaires have primarily focused on learner behavior (the frequency, quantity, and diversity of informal activities in which learners engage), the ISLE additionally targets affective, cognitive, and linguistic aspects of engagement. Consequently, this questionnaire has the potential to help second language acquisition researchers better understand individual differences and variability in informal language engagement, how it changes over time, and the ways in which engagement affects language learning. The ISLE was developed and evaluated in three stages with a total of 382 German secondary school learners of English as a foreign language. The initial instrument development was informed by qualitative findings from focus group interviews. Subsequently, the questionnaire was piloted, and Exploratory Factor Analysis was applied to the data to uncover the underlying factor structures and reduce the number of items per construct. Finally, the revised instrument was evaluated further using Confirmatory Factor Analysis.

本文报告了非正式第二语言参与调查问卷 (ISLE) 的开发和验证，该调查问卷用于捕获学习者参与非正式第二语言实践的各个方面。其他调查问卷主要关注学习者行为（学习者参与非正式活动的频率、数量和多样性），而 ISLE 还针对参与的情感、认知和语言方面。因此，这份调查问卷有可能帮助第二语言习得研究人员更好地了解非正式语言参与的个体差异和变异性、它如何随时间变化，以及参与影响语言学习的方式。ISLE 分三个阶段进行开发和评估，共有 382 名以英语为外语的德国中学学习者参加。最初的工具开发是根据焦点小组访谈的定性结果得出的。随后，对调查问卷进行了试点，并对数据应用了探索性因子分析，以揭示潜在的因子结构并减少每个构建的项目数量。最后，使用验证性因素分析对修订后的工具进行了进一步评估。