This thesis investigates upper secondary students’ usage of scientific and colloquial language through a custom-designed game. The aim of the game is for the participants to, without any time limit, explain chemical concepts using other words than the one written on the playing card so that the partner is able to guess what the target concept is. During the audio recorded game sessions the students showed usage of scientific and colloquial language as well as a blend of these two linguistic resources. The students also used metaphors and helpwords in some measure together with a linguistic resource that seems to border to spontaneous metaphors and helpwords, here referred to as ‘phonetic metaphors’. These phonetic metaphors seem to lack a direct connection to the chemical meaning of the target concept in return for its phonetic connection to the concept. It though seems like the students’ usage of these different linguistic resources may support meaning making processes as well as memorization processes. The thesis concludes with a discussion according whether this game, if used professionally and thoughtfully, aligns with the guidelines for Assessment for Learning specified by the Assessment Reform Group and whether it may function as a tool for assessment for learning in practice.