The aim of this paper is to describe the platform, offer concrete examples of its content and functionalities and present the results of an extensive evaluation process. The description of the platform covers the following key components: a) one hundred (100) structured lessons depicting different types of language phenomena related to morphology, vocabulary, semantics, syntax, spelling and punctuation, text comprehension etc., b) thirty (30) revision tests, which have been designed for both self- and classroom assessment, c) additional lessons prepared by teachers to cater for the specific needs of their students, d) a dictionary of more than 11,500 single- and multi-word entries covering mainly the basic vocabulary of Greek and a number of technical terms from various subject areas, e) a database of standard diagnostic tests to select students for additional supportive courses in Greek, f) a database of progress reports exchanged among teachers and school counselors, g) a forum to support communication among teachers and school counselors and h) a management system that allows teachers to organize virtual classrooms, upload multimedia material and prepare their own lessons in any way they see fit. To further describe the content and functionalities of the platform, one language lesson and one dictionary entry are explored as examples. To ensure the quality of the end product, ‘Glossa for EPAL’ was evaluated both internally and externally. Throughout the development phase, developers ran various checks on every part of the platform to ensure the top quality of the teaching material, the user interface and its various functionalities. In order to conduct external evaluation, the platform was implemented in school classrooms and teacher training seminars. Actual users, both students and teachers filled in evaluation questionnaires. The paper ends with the conclusions from the external evaluation process.