Steinbeck’s writing style mirrors his characters. Of course the author writes as the men would literally speak, but on a deeper level, the language of the book is simple but compelling – just like the characters. Because the language is easy to understand, it’s even more extraordinary that it can carry such lofty themes, feelings, and ideas.
Though the characters never gush about each other, it’s clear that they feel deeply. Steinbeck achieves this by using simple language to build characters who are more than what they say. For example, while George says he and Lennie just got used to each other, what he’s really feeling is that their friendship is the only thing he’s ever really had to hold on to. The language, like the men on the ranch, seems simple enough, but it’s more "still waters run deep" than "OMG you’re my BFFL."
Again, Steinbeck uses his writing style as another means to suggest that every story is important, no matter whose story it is. Though these characters are working class people who don’t have access to big vocabularies or grand philosophies, they can still communicate about the things that really matter.
This all comes through in the dialogue that dominates the book, and is only occasionally augmented by the narration. The narrative style can differ slightly from the simplicity of the dialogue (like when the narrator is so effusive in describing Slim), but usually even the narration tells the most gripping stuff in a straightforward manner. When George kills Lennie, Steinbeck lets the language be as stark and straightforward as the act, making it all the more shocking. Part of Steinbeck’s brilliance is this subtle usage of language: when he needs to make words sing, he can, but usually he’s good enough that the action doesn’t seem like it’s clouded over with poetry. Instead, it just reads like real life.