As children, most of us are introduced to animation at a very young age. This animation is almost always orthodox animation. As Wells states in the article, the most prominent company to produce this type of cell animation is Disney. It is a very realist type of animation that is based on many things, most specifically, narrative form and continuity. These types of animations are most commonly made by many different artists, and follow a story. They are most often animated after a soundtrack is made.
Another clear difference between experimental animation and orthodox animation is the role of the soundtrack. Orthodox animations have dialogue like in a narrative film, where as experimental animation often has a more musical soundtrack that must be interpreted by the viewer. Experimental animation is often more ambiguous, and it is left up to the viewer to interpret the film. It is also important to take note of the fact that in experimental animation, the soundtrack doesn't always correspond directly to the visual.
I think is is really important to take note of these differences in order to understand the difference between experimental animation and mainstream or orthodox animation. Where as orthodox animation is more like a novel, experimental animation is more like a poem. Experimental animation leaves it up to the viewer to take something from the film.