Mobile Learning Games (MLGs) show great potential for education, especially in fields that deal with outdoor learning activities such as archaeology or botany. However, the number of MLGs currently used remains insignificant. This is partly due to the fact that the current authoring tools are based on modeling languages that only allow creating very specific and rigid types of MLGs. In this paper, we therefore propose an extensive modeling language for MLGs. This model was designed, with the help of botanical experts, in order to cover the variety of MLG types they would like for their field trips. This modeling language uses high-level concepts, such as game activities and points of interest on a map that can therefore be used by teachers in any domain. Finally, we discuss how scenarios, described with this language , can be automatically transformed into executable web applications.