It's amazing how loud parrotlets can be, we have 5 of them right now and I can relate! We also have a macaw, IRN, quaker, which are much louder, believe me
I wouldn't think your bird would be loud enough to really bother your neighbors, though, not like a macaw. Do you keep your bird in the room where you spend most of your time? Birds are very social and like to be near you. whatever you do, don't get her a bf, you will just end up with more parrotlets and more noise! Toys, treats, covering up the cage, all will help with some of it, but along with owning a pet bird comes noise, some are quieter than others, but all make noise in some way, you gotta love em, though. Good luck with your little Fern (cute name!)
Martha