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.