Both drawing and language are fundamental and unique to humans as a species. Just as language is a representational system that uses systematic sounds (or manual/bodily signs) to express concepts, drawing is a means of "graphically" expressing concepts. Yet, unlike language, we consider it normal for people not to learn to draw, and consider those who do to be exceptional. Why do we consider drawing to be so different from language? This paper argues that the structure and development of drawing is indeed analogous to that of language. Because drawings express concepts in the visual-graphic modality using patterned schemas stored in a graphic lexicon that combine using "syntactic" rules, development thus requires acquiring a vocabulary of these schemas from the environment. Without sufficient practice and exposure to an external system, a basic system persists despite arguably impoverished developmental conditions. Such a drawing system is parallel to the resilient systems of language that appear when children are not exposed to a linguistic system within a critical developmental period. Overall, this approach draws equivalence between drawing and the cognitive attributes of other domains of human expression. (Contains 5 figures and 1 table.)