You could also try those no-bark things they have. Its a small box and you can attach it to the wall outside and it emitts a high pitched sound when the dog barks that they hate and its supposed to teach them not to bark. I have heard they work well but they are a little pricey at around $100; but you'll only need to buy it once. Also, if you are keeping him in the garage and are worried that he thinks its a punishment give him treats and lots of praise for staying in the garage so he knows its a good thing and a good place not a punishment. You can have toys and blankets, a bed, in there too to make him more comfortable and so he knows that's his sleep spot.
I read on another post of yours that you live by a highway so maybe that's why yoshi is barking too because the cars are loud and it's busy?? He could also be distracted with so many things going on outside if he is wondering around and barking instead of sleeping at night. Maybe he thinks that night is play time so you could try getting him into more of a routine and try teaching him that night is sleep time. Also, Do you have a dog house or anything for him? Dogs need an established place to sleep that is like their 'den' or 'cave' so you could try that? Plus, maybe it's not such a good idea to leave him outside all night by himself if you yard is not fenced; you don't want him to get into trouble with the highway or your neighbor
