One of mine was a bit barky as a pup, started at about 9 months :rolleyes: The way we dealt with it was not to give in !! Any barking meant that all fun would stop immediately :( and if it persisted then the dog was sent out of the room for a few minutes and only allowed back in if quiet. This may be harder to do if the barking never stops, but there are ways of dealing with it.
Dinner - dogs have to sit by front porch door and wait untill called to dinner in kitchen (they love this as its fun!! ) this was the cue to bark, but the dog was not allowed to move until barking stopped and if barking started on the way got sent back to the beginning, each time taking longer to call him ;) so if I waited 20 seconds the first time, it increased by 10 seconds every time he got sent back, first day he had to wait half an hour longer for his dinner!! ( the other one had eaten his

) he quickly cottoned on and now is mostly quiet when waiting for dinner.
When in the garden any barking means they have to come in (stupid human misunderstanding them :rolleyes: )
Any other barking I would treat by waiting for a pause and then giving attention.
eg. wanting to go out at night - I would go down and wait until the barking stiopped before going in to the pup and letting her out.
Wanting in from the garden, wait until barking paused before opening the door :)
If you can use a clicker (good ones come with instructions for training to the click/reward) then you should be able to stop the barking fairly quickly, every time there's a pause of a few seconds click and treat, once the dog has the idea you can increase the length of time that the pause lasts. You may have to use a small noise distraction to get him to stop barking at first.
Remember though that all people in the household have to be consistent with what you're trying to do or it won't work!
Hope this helps a little, someone else will be along soon to offer more/different ideas which I haven't thought of.