What is the best legal was to deal with a REALLY noisy neighbor?

I live in a duplex and the walls are pretty thin cause it's a very old house that was remodeled to be a duplex. I have a 16 month old son and try to keep him on a set schedule as far as naps and bedtime goes, but this neighbor is HORRIBLE! He has a little dog that yaps at all hours of the day and night, and most nights we are kept up by him and his friends. In fact, some nights he is so loud that I can recount the entire conversations he has, and they're actually very offensive if he has female company. He is foul mouthed and chooses to express himself by yelling more often than not. Not to mention that most of this happens from 9:30 pm til whenever they pass out. My husband has to get up about 4 am 6 days a week to go to work, and it makes it impossible to get my little guy to bed at a set time most nights. It doesn't matter where you are in the house, when they get going next door, you can hear it. What should I do? We're not very confrontational, and I'm 5 months pregnant so between the losing sleep and hormones I wouldn't be the best to talk to him and my husband works almost 16 hours a day and doesn't have the time. I need some major advice?