Coming to appropriately appreciate the meaning of algebraic signs is an important aspect in introductory
kinematics. However, in this educational context, the “disciplinary relevant aspects” of algebraic signs across
vector and scalar representations are extremely difficult to discern. Our study explores the “relevance
structure” that one-dimensional kinematics problems evoked for introductory level university physics
students across two very different educational systems which have, in PER terms, progressive teaching
environments: Sweden (n=60) and South Africa (n=24). The outcomes of two previous PER studies are used
to provide the analytic basis for formulating categories of relevance structure. Aspects of a contemporary
PER-developed social semiotics perspective (referred to here in terms of communication practices) are used
to discuss implications for teaching in the given educational context of introductory kinematics.