Henry and his fellow infantry soldiers speak in a colorful American vernacular dialect that testifies to their humble origins. In the novel, Crane renders that dialect phonetically. For example, in relating a (probably false) rumor about spectacular Union victories, a soldier in Henry's regiment says:
I met one of th’ 148th Maine boys an’ he ses his brigade fit th’ hull rebel army fer four hours over on th’ turnpike road an’ killed about five thousand of ’em. He ses one more sech fight as that an’ th’ war ’ll be over.
The dialect of the direct speech between officers contrasts with the relatively high register of Crane’s narrative voice and especially his representations of Henry’s thoughts, which are formal and almost stilted. That contrast in language reflects a broader contrast between Henry’s naive conceptions of heroic classical warfare with the alternately brutal and prosaic reality of being a soldier in the Civil War.
Officers play minor roles in The Red Badge of Courage. When they do speak, they use standard English, showing that they enjoy more education and higher class status than the enlisted soldiers. But while the vernacular exchanges between enlisted soldiers are generally good-natured and sincere, the officers’ speech demonstrates their condescending and callous attitude towards the men they command. In one exchange that Henry overhears, an officer refers to his regiment as “a lot ‘a mule drivers” and casually volunteers to send them to a frontline action where casualties will be high, as if their lives are completely dispensable. The general with whom he is speaking simply replies that most of the “mule drivers” won’t survive. The officers may speak beautifully, but they do not share the camaraderie of the enlisted men and they are far more callous about the loss of life war entails.