Dialog game tools are text chat applications which aim tostructure and promote students' collaborative learning byhaving them select a label and sentence-opener for eachmessage they type to their learning partner. In thisexperiment, we compared students’ learning from discussionsvia a dialog game tool to their learning via a standard freechatapplication. Students discussed topic questions with alearning partner. They then individually completed a multiplechoice test, for assessing knowledge-gain, and a short-answertest, to assess readiness for knowledge-building. Resultssuggest that dialog games applications lead to increasedreadiness for knowledge-building, in the form of integratingdistinct pieces of learned knowledge, than freechatapplications. Follow-up analyses suggest that the degree ofconcept overlap between students' dialog messages and topickeywords, as measured by a "semantic fingerprint" system, isa potentially useful metric for predicting students'knowledge-building. Implications and potential applicationsof our findings are discussed