Walt Whitman's Poem "I hear America singing" like any poem is littered with metaphorical figurative language. In saying so Walt Whitman literally does not hear America singing, "Singing" is instead a metaphor for the everyday working class of America. So "Singing" in this case represents "work". So should Whitman have heard America speaking the poem would lose its tone, changing the point in its entirety, losing its enthusiastic and happy nature. So should America be speaking then the people of America would not be happy with their very jobs, and thus being instead content, or unhappy with their lives.