A language device is a special way of using words. One language device Steinbeck uses to show the relationship between George and Lennie is paternal is dialect. Dialect is language specific to a certain group. The dialect demonstrates that George and Lennie have background in common.
When the story opens, George is telling Lennie not to drink scummy water.
"Tastes all right," he admitted. "Don't really seem to be running, though. You never oughta drink water when it ain't running, Lennie," he said hopelessly. (ch 1)
The use of slang and familiar words continues throughout the story, and shows that George and Lennie are close and have a paternal relationship. George talks more often than Lennie, and Lennie often repeats what Geroge says because he looks up to him. Lennie knows that George is protecting him and looking out for him.