Why is the study of language called Language Arts, not Language Science?
It seems to me that the study of language is more of a science than an art. It functions like a science with principles and rules that govern it. When i think of art, I think of something that has no firm rules, like poetry and sculpture. Anyways, this will be bouncing around my head, until I get an answer here, or google it.
The study of language actually is a science - linguistics - whereas language arts is more commonly the study of literature, poetry, and such. It's a common mistake to make, so I'll elaborate a little.
Language arts is generally more concerned with style, form, history, and aesthetics, less on the grammatical structure. It deals more closely with the overall form and shape than the nuts and bolts. This is what literature and English professors primarily do.
Linguistics is the empirical study of the small moving parts of language - everything from grammar to usage to how language interacts with the brain. Linguistics doesn't necessarily care about literature - it often does, but not always - rather linguistics is primarily concerned with how and why we make language, and how that interacts with other aspects of human life.
There is a common misconception that linguistics is an art not a science (most universities with linguistics programs will give you a Bachelor of Arts degree), primarily due to the confusion that any language study is an art, like the study of literature is.
I hope this answers your question in a bit more than broad strokes.