  We utilise Richards-Engelhardt framework as a tool for understanding Natural
Language Processing systems diagrams. Through four examples from scholarly
proceedings, we find that the application of the framework to this ecological
and complex domain is effective for reflecting on these diagrams. We argue for
vocabulary to describe multiple-codings, semiotic variability, and
inconsistency or misuse of visual encoding principles in diagrams. Further, for
application to scholarly Natural Language Processing systems, and perhaps
systems diagrams more broadly, we propose the addition of "Grouping by Object"
as a new visual encoding principle, and "Emphasising" as a new visual encoding
type.
