Practitioner journals differ from research journals in that they feature articles written primarily by professionals in a given field (in this case, teachers!). These articles often feature real-life experiences or observations, and are geared towards offering advice, establishing best practices, and noting trends within the field. Articles may still be scholarly, but they are not always necessarily reporting original research.
Research journals differ from practitioner journals in that they typically feature original scholarly work. Articles are more likely to be primary sources, featuring the methods and results of a study conducted by the author(s). Research journals are almost always peer-reviewed.