Comic books have their own structure, conventions, and language. In a seminal 1988 essay, two cartoonists broke down elements of this syntax using a single Nancy comic strip.
How to Read Nancy breaks down every aspect of a Nancy comic strip from 1959 to show the purpose and meaning behind every design choice, from the panel shape and structure to the placement of word balloons, shading, groundlines, characters, and props.
This essay is often used to teach the analysis of comics; the Wikipedia article suggests that a quarter of higher education courses on comics use this essay as a required reading.
For a more extended look at comic syntax, it’s also worth checking out the longer and more detailed Understanding Comics and Comics and Sequential Art.