In this project, I want to continue my research on individual differences in language proficiency and related skills. Even among university students there are large differences in language proficiency as measured, for example, with a vocabulary test. However, there are very few tests available for this population. I myself have developed two tests for Dutch vocabulary, which are widely used. We have also developed tests for English (Vermeiren et al., BRM, 2023), which are also used by several groups. This project should make it possible to continue this research. For example, I want to examine how the different tests relate to each other: How strongly are vocabulary and grammar related? And how do the two relate to text comprehension? Are there differences between implicit language knowledge and explicit language knowledge? The former is acquired by using language, the latter by learning rules. This may make a difference especially for people learning a second language. In addition, I also try to understand why there is a correlation between reading pleasure and empathy (e.g., Hendel & Brysbaert, submitted). Such research is only possible if good, validated tests are developed for each skill.