Walt Whitman in his poem "I Hear America Singing" has as his intention to tell us how he interprets the various sounds he hears. Americans make different noises but when you put them together they blend into a symphony that could only happen in America, he said. That, of course, is an overstatement in the way most of his poetry is, but that's why America is fascinated with him. It's that patriotism that sets this poem apart and makes it provocative, and elevating it beyond euphony. His carefully chosen words show him empathetic toward those who worked hard and made this country a thriving nation. It's his way of sharing his thoughts and his idealism. Maybe it's his way of saying 'thank you'.
As for scansion it does not fit in any other poetry type other than that of the type he writes. He was much more spontaneous as a poet than to be fenced in in terms of rhythm and meter and he preferred to listen to the word sounds and to respond in his own way. He sings his song right along with the varied workmen he hears plying their trade. He calls their songs carols and this is interesting and quite fitting.
Had he been living in today's world and not thinking about singing, on hearing an incongruous bunch of noise makers he might have labeled them rappers, or rock stars. But as it were, or as it appears to me while reading lines such as "I hear America Singing, the varied carols I hear, those of the mechanic. . . The carpenter. . . The mason. . . The boatman. . . The shoemaker. . . The woodcutter's song, the plowboy's on his way in the morning, at noon intermission or at sundown. . . ", he was not so much hearing music in the sounds that the various activities create as he was determined to make music out of them.
He was probably feeling these common workmen to be kindred spirits and wanted to honor them. After reading the poem I do not get the music from these sounds he talks about as I do when I read his other poems. In these more personal poems he lets it rip. He lets the words speak for themselves with little interference from his thinking and rational mind.
And truthfully, the whole work is contrived. Surely he is not referring to music in the sense of harmony and singing and pleasant sounds but it is his appreciation of the endeavor of these hard working sweating and tired people that gives this carol its melody. This is your music, he is saying to the hoards that cannot sing while they work, or are too tired after a long day in the fields plowing, or pounding nails.
I know for a fact that women bent over a washboard back in those days did very little singing out loud but may have done a little praying that the sun would shine and that the rain would would hold off until the clothesline of half-dry clothes were dry and safely inside. Whitman was in touch with his world because he enjoyed it so much and sang of it every day; he wanted it for others.
"Each singing to what belonged to him or to her and to no one else. . . " told me that the world Whitman sang of was of his own inner world. He somehow understood, however, that others would not necessarily hear what he heard when he thought of them through the messages he received from his very own personal drummer. The poem is good enough but it is not one of his best. Out of several books of poetry that has poems by Whitman, this one I found only in an old textbook "The United States In Literature" that has a copyright notice of 1952. Again I say, it's not that the poem is not appealing, as it is, but truthfully the country does not sing that way any more.