In order to examine the dialogue an author chooses to write with, one must first understand the different aspects of dialogue.
First, there is the tone of the dialogue. Tone is the attitude the author, and therefore, the speakers, take with the ideas presented, other character, and the audience (the readers).
Second, there is the aspect of dialect. Dialect is
the language of a particular district, class, or group of persons. It encompasses the sounds, grammar, and diction employed by a specific people as distinguished from other persons either geographically or socially.
Therefore, in order to examine the dialogue which Steinbeck uses in the novel Of Mice and Men, one must first be familiar with the setting, the types of characters involved, and the feelings of the author based upon the situations described.
Given that the men in the novel are farmhands, and assumedly uneducated, one can see this in their choice of words.
In a conversation between George and Lennie in chapter one, a reader can see the typical dialect of wandering farmhands:
"No reason at all for you. I like it here. Tomorra we’re gonna go to work. I seen thrashin’ machines on the way down. That means we’ll be bucking grain bags, bustin’ a gut. Tonight I’m gonna lay right here and look up. I like it."
The dialogue is filled with references to farm machinery and slang. This would have been typical of men like Lennie and George.
Therefore, in order to examine Steinbeck's use of dialogue, one would need to begin with research on the dialect of ranchers in California during the Great Depression era.