DerLex is a large open database of eye-tracking data on **English derived words** (e.g., *teacher, permission*). It’s designed as a **companion to CompLex**—our earlier eye-tracking megastudy of **English compound words** (e.g., *goalpost*)—so researchers can study two major types of morphological complexity using comparable methods and compatible data structures. This project was published in [Behavioral Research Methods](https://link.springer.com/article/10.3758/s13428-024-02565-3).
Many words in English are morphologically complex (*assign*-*ment*, *teach*-*er*) and so being able to proficiently apply the correct endings (suffixes) to complex words is an important skill to acquire. In this project, we analyzed the written production of English language learners and asked *What are the statistical properties that make morphologically complex words easier for EFL students to learn?* This project was published in [Applied Psycholinguistics](https://doi.org/10.1017/S0142716422000182).