As a thesis statement for discussing how language influences the audience (reader) of a poem, you are sort of stuck in a redundancy--the poem is all language. How about something like "What social conventions do the speaker and the neighbor share?" The whole poem is a portrait of New England rural life--make an essay out of that.
Your thesis statement (essay means "to try") must state an arguable point of view--start with that. Perhaps yoy could argue that the poet/narrator and the neighbor are not alike--different crops, different attitudes toward tradition, different senses of humor, different language skills, different educations, etc.