Frame/content (F/C) theory  offers a working rationale of the rise of serial-order control and forms without assuming a priori units. A synthesis of our recent work is presented with the purpose of refining this rationale on two points. First, observations of contraction activity and passive elasticity suggest that basic frames of serial-order control correspond to contraction-relaxation cycles not present in non-speech motions such as mastication. Second, on explaining prosodic grouping, results show a relationship between size effects on such patterns and grouping effects on recall. Converging evidence suggests that grouping may arise from capacity limits on attention processes of short-term memory.