What does Winston see and hear under the window while in the secret room?
Winston sees and hears a large (Winston at first calls her "monstrous"), older prole who hangs laundry and sings in the courtyard below the window of the room above Mr. Charrington's shop. She seems to be constantly hanging diapers. She has a good voice and makes the popular tune she sings sound "almost pleasant."
This woman is important because she provides such a sharp contrast to the average Party member. She sings spontaneously, something that Winston notes Party members never do. Further, she seems happy and at peace with her life, a state of being also not usual for a Party member. As Winston puts it:
One had the feeling that she would have been perfectly content, if the June evening had been endless and the supply of clothes inexhaustible, to remain there for a thousand years, pegging out diapers and singing rubbish.
Right before he is arrested, Winston shows he has become fully re-humanized when he realizes the washerwoman, though a prole, is fully a human being, and he even thinks of her as beautiful. He realizes that she lives the kind of ordinary, everyday life surrounded by family which was once the normal way people lived, and he realizes that it is her kind that holds the keys to future. He thinks to himself as he watches her:
If there was hope, it lay in the proles!
He sees and hears a prole woman who sings melodies created by the party. This gives Winston a strange sort of hope, as he sees natural human expression, even though all are trapped in a totalitarian society.
Winston sees and hears a solid-looking prole woman from the courtyard who was singing a melody, created weeks before by a versificator from the Music Department by the Party, as she hangs her laundry on the clothesline to dry. He had written in his secret diary that all hope for the future must come directly from the proles, so this amazing sight that he saw outside the windows gives him a sense of hope and fulfillment and becomes a symbol of the "hoped-towards-the-future" to Winston and he visualizes that the woman would bear many children that who would one fine day overthrow the totalitarian society, the Party itself and bring about peace and harmony, no more brainwashing and monopolizing and deception to bear any longer.