Cognitive dome

A cognitive dome is a figure used by Sydney Lamb (2016). Imagine a sail dome, also known as a sail vault, which gives the impression of a square sail pinned down at each corner and billowing upward. The pinned-down corners or "legs" are (1) speech input, (2) speech output, (3) extra-linguistic perception, and (4) extra-linguistic motor activity. That is, the legs connect the cognitive system to the external world. The surface of the dome is the cognitive system itself. Semological structure is the large area at and near the top.

Discussion
The dome is only a rough aid to visualizing the actual situation, since what we really have is a separate leg for each perceptual modality, and several to many legs for motor structures, depending on how we choose to count.

As the figure suggests, the numerosity of distinguishable features is greater at higher strata than at lower. For example, in spoken language we have only about a dozen articulatory features, two to three dozen phonemes, a few thousand morphemes, tens of thousands of lexemes, and hundreds of thousands of sememes. The same type of relationship evidently exists for the other systems.

The conclusion of this line of reasoning is that meaning structures are not simply above lexicogrammatical structures, in the same way that lexicogrammatical structures are above phonological structures. Rather, they are all over the cognitive system: Some, including concepts, are above, while others, including percepts, are not.

At this point we encounter the question of how far linguistic structure extends. We could take the position that these other systems are not part of linguistic structure and therefore don’t have to be included in the investigation. That proposal would lead to an impoverished understanding. Conceptual structure and perceptual structure and the rest are so intimately tied up with the rest of linguistic structure that the latter cannot be understood without including the former. There are two major reasons for this conclusion: (1) the semological categories are highly relevant to syntax; (2) semological structure is largely organized as a hierarchical system of categories, and this categorical structure, along with the thinking that depends on it, varies from language to language and is largely learned through language.

Moreover, the boundaries between conceptual structure on the one hand and perceptual and motor structures on the other are also at best very fuzzy, so there seems to be no clear boundary anywhere within the cognitive dome. And so the quest for boundaries for language comes up empty: There is no discernable boundary anywhere within the cognitive system. We conclude that the investigation of linguistic structure takes us to a way of understanding cognition in general, including the structures that support perception and motor activity.