How does Hughes describe the American identity?

The speaker claims that he, too, sings America. He is the "darker brother" who is sent to eat in the kitchen when there are guests visiting. However, he does laugh and he eats well and grows bigger and stronger. Tomorrow, he will sit at the table when the guests come, and no one will dare to tell him to eat in the kitchen. They will see his beauty and be ashamed, for, as he claims, "I, too, am America.