For example, PG and DP need a vocabulary for discussing the representation of book contents that is familiar, precise enough, and comprehensive enough to discuss how they will represent the book and how PG will interpret their representation. The common language I would expect woutd include paragraphs, headings, chapters, poetry, emphasis, tables, illustrations, captions, viewing devices (screen capabilities and controls), ebook identification, acquisition, distribution, storage, maintenance, ... These are all concepts that have roughly similar meaning to both sides. And you need to agree on the scope and workflow in which you mutually participate; and have a roughly good idea what the participation feels like to each other. When the conversation instead devolves around markup and divs and floats and margins and RCS, you no longer are discussing the problem domain, nor are you using vocabulary that is equally useful and meaningful to both of you.