Hi -- I agree with everything Anne said, but I'm going to do some plain speaking here as well. WE don't know you at all, so please don't misunderstand -- I'm not getting up your nose or being nasty -- but also trying to help explain this a bit.
First off -- your post talks bout them barking outside -- and I'm getting the feeling these started out as inside dogs, that probably drove you nuts barking inside, and so now they're outside, maybe most of the time (because they drive you nuts barking)??
Realize dogs bark for several reasons.
1. They bark to communicate -- with their pack (YOU, frustrating as it may be for all 3 of you), and with each other, but also as a warning to those they want to go away.
2. They bark out of boredom or frustration (a lot of that in this).
3. They bark to scare away things they are unsure of or fear (more than possible here).
My guess is that you may not be a 'dog person' -- and you are simply honoring a parent's request. But you may not have the first idea of how to relate to these animals, nor figure out how to get them to behave enough TO tolerate them. That's no condemnation -- that is simply "understanding" -- and you'll find help here if you're willing to work on this from a logical perspective.
But it will take time. And effort.
My initial guess is that the dogs likely sense your frustration and perhaps your dislike so they aren't motivated TO obey you or work with you. Dogs grieve -- sometimes they grieve a lot. And the guess is that probably your parent wasn't very good at training to begin with. Perhaps just gave in and doted on them. But likely didn't put them in a position where they barked out of frustration or boredom as much.
Honestly, training is the only suitable answer here. You may have absolutely NO interest in clicker training or positive nuthin! But ... let's explore the alternatives.
You continue as it is -- eventually you are going to get rid of them because you (or your neighbors) can't tolerate the noise.
You try to ignore it -- that won't work and it will make you angry -- that will make you resent yourparent's memory among other things. Guilt.
You just get rid of them -- against the wishes and you agreed to care for them ... guilt (and anger).
Or ... you do what is necessary to deal with them. And frankly -- training DOES work. And in total honesty .. you may just find out what it was your parent saw in them. You may find there lurks inside of you a 'dog person' you never knew was there.
Can I suggest things to read?
There are books aplenty -- but just do an internet search for this whole line (quotes and all)
"Nothing In Life Is Free" dog training
You'll get a lot of hits -- with a lot of ideas, but mostly very similar stuff. Most of it written for people NOT saavy about dog training. But you will find that with just some modifications to how you feed them (you don't feed them until they 'sit' and are 'ready' and then you put the bowl down). But pretty quickly you will get some results positive for you.
Once you get some results, you'll find it's easier to contemplate "dog training" per se.
It can work. It can be very rewarding. please ... give it a try.
But I can promise you ... the problem isn't JUST barking. The problem is that they have not a clue how to obey you. They may, in fact, not really have a clue how to 'obey' anyone. And when a dog does obey you ... it's really pretty darned pleasant. But getting communication going between you and the dogs so they understand what you want (and one of the things you "want" is them NOT to bark!! They don't get that! No matter how you yell, or get frustrated -- they don't understand that.) -- but once there is some responsive communication between you and the dogs it will seem more possible.
Please -- let us help. There are a lot of good people on here who care. And honestly? Anne IS a trainer .. it's what she does!! And you're getting freebie help here!