The thing that confuses me about this wonderful concept is how did the Tamarians ever get to the point of building wooden ships if they only spoke in meme and metaphor? How could they have created a culture that speaks only in references if their references couldn’t happen without culture existing to make note of the referenced events?
I saw an amazing post on the alien site a while ago—I think it was in Daystrom, but I’m not sure—that suggested the Tamarians may have 2 or 3 different “modes” of speaking. This would explain both how their language’s function words exist and how children might acquire language.
I think this probably happened the other way round. They had a separate more traditional language until they struck out and discovered other civilizations that spoke other languages. An allegorical language that can be modified with context under observation would actually be a fairly good way to relate and then exchange languages using tamarian as sort of a Rosetta stone.
I assume that they didn’t always speak that way, but as their language evolved it became gradually more dense with allusions, until they took over entirely.