Abstract : This article focuses on the development of Natural Language Processing (NLP) tools for Computer Assisted Language Learning (CALL). After identifying the inherent limitations of NLP-free tools, we describe the general framework of Mirto, an NLP-based authoring platform under construction in our laboratory, and organized into four distinct layers: functions, scripts, activities and scenarios. Through several examples, we explain how Mirto's architecture allows to implement state-of-the-art NLP functions, integrate them into easily handled scripts in order to create, without computing skills, didactic activities that could be recorded in more complex sequences or scenarios.
