Explaining geometrical concepts in sign language and in spoken langua...

The explaining of mathematical terms is part of both learning and teaching mathematics. In this study, explanations, in the forms of a video in sign language, a video and an audio recording in spoken language (all on the subject of quadrilaterals), are compared. Therewith, the explanation process is understood as semiotic mediation, as proposed by Hasan (2002, 2005). The question regarding which role the modality plays in transitioning from specific geometric forms to general statements of the geometric forms is also pursued.