Recently, while I was discussing this idea of vocabulary peculiar to art, I realized it would be necessary to differentiate between the vocabulary we all had to learn in our elementary education that helped us build our communication skills and the kind of vocabulary that is often the result of learning a specific skill. Anyone that has learned a technical skill knows that there are ways of discussing items or situations unique to their training that a layman would not understand. It is the same with art, we learn things that non art people would never image and certainly could not understand without some amount of tutoring.
When we refer to art vocabulary there are the two lists, one of the Elements: Line, Shapes, Value, Color, Texture and Space and the other of the Principles: Variety, Contrast, Balance, Rhythm, Movement and Unity and then there are all the descriptive words that make the Elements and Principles come alive. For instance how many different characteristics of lines can we describe? Lines can be straight, curved, wavy, thick, thin, broken, repeated, dotted, jagged, looped and on and on. The more descriptive words we know for any of the Elements the better we can talk about what we see. If we have studied, experimented with and applied the many different characteristics of any of the Elements of Design our art will already show the depth of our knowledge.
The study and experimentation of the variety of characteristics of the Elements of Design can be called a process of discovery. We cannot really expect to have a broad visceral knowledge of how the multitude of variations of the Elements can function in our art without indulging in a process of discovery. Certainly, over time, great effort and significant experience will result in accumulating some of this knowledge. But there is no substitute for a serious focused investigation of the design potential of any of the Elements.