Those who draw will be better at seeing, and those who write will better understand.
Like anything used on a consistent basis, our eyes are open to being taken for granted. The eye allows us to see the objects that make up our reality by constantly taking in information that we, fortunate enough to have sight, use to survive as well as interpret our surroundings. The spaces and forms we see frequently dictate how we think about the world, subconsciously and consciously.
Drawing forces the viewer to observe the connections within and around an object, as well as it's relationship to themselves. By drawing, you inevitably learn more about space, forms and relationships.
Language is the tool that allows a person to communicate their thoughts with others, and makes writing an activity that forces a person to analyze their thoughts. Because communicating to others means you must have an understanding of the subject yourself, writing helps concrete or actualize your understanding.
Like any other art, drawing and writing are skills resulting from practice and learning. By continuously drawing, you will better see, and by continuously writing, you will better understand.