We created a reading app (called Hibou) which presents normal and simplified texts of the Alector corpus in a gamified environment. The Alector corpus is an open-access database in which texts can be chosen as a function of different criteria: length, age, type of text, and text difficulty. The texts are available in normal and simplified versions, with identical comprehension questionnaires for both versions. The whole set can be downloaded in PDF format.
Javourey-Drevet, Dufau, François, Gala, Ginestié, & Ziegler (2022) Applied Psycholinguistics.