The people across the street have apparently decided that they still do not, as a household, make enough noise. Despite the constant honking of various vehicles at all hours of the day and night, despite the constantly screaming children and yelling adults, and despite the loud booty-bass music either from cars or their home stereo. No, that's not quite enough. So for the times when they are asleep and can't actively be outside making noise, they now have a dog—-I want to say "puppy," because it's not quite grown up yet, and yelps like a puppy.
They keep it tied to the porch most of the time, from what I can tell. Sometimes it seems to be yelping and squealing out of boredom and loneliness. Other times when they are out there with it, it yips and shrieks out of what sounds like pain or surprise, or sometimes apparently because it's being ignored.
I would guess that it has Stockholm Syndrome and has learned to identify with its captors, equating torture and teasing with love and attention. What the heck do they have it for, if they're going to keep it tied to the porch all the time?
I guess a watchdog, either to protect them from the crack dealers in the next apartment or else to protect their stocks of crack. (I can't quite tell exactly who's dealing and who's not.)