I have a girlfriend with a totally deaf dog that uses sign language. It may take longer for them to learn this???? I would use the signs just like you are doing. In our classes we used signs and Sage sometimes still prefers to ignore them...only treat for the full trick or you're setting him up to never learn what you want and yourself for getting frustrated. Good luck!
How do you know he's "hard-of hearing" as opposed to "hard-of-listening"?
Hand signs work well with dogs. I'd thought you teach "down" by palming a treat palm-down on the ground by the dog's nose. Hunters use hand signals (and whistles) with retrievers. You could probably invent a hand sign to accompany every verbal command. Try it.
The famous border collie with a vocabulary of over 200 English words got a lot of extra verbal attention as a pup because it was feared to be hearing-deficient.
Funny, that was exactly my first thought when I read this post ;->
Teaching Watch Me would probably help. You say watch me (this works great with a piece of cheese in your mouth) and when they make eye contact, they get a piece of the cheese. Work up till they can hold your eye contact for a good 10 seconds or so. Then, before you give a command, you can ask them to Watch Me and then give the command, and you'll get good eye contact and know they're paying attention. Also, they suspect that cheese may be imminent, and that helps corgi pay attention a lot. Cheese is corgi Ritalin.
I don't think he is hard of hearing I think you are just not taking the appropriate approach. Remember he has NO IDEA what all these words mean. You should NEVER ad a word to a trick until the dog is doing it at least 80% of the time. What I mean by this is, say you are teaching him "down" you put a treat on the ground and cover it with your hand, at the same time you have a leash attached to his collar and apply downward pressure on the leash essentially pulling him into a down, he sniffs the treat, does all kinds of crazy things to try to get it and struggles to get away from the pressure on his collar, then eventually he lays down, he immediately gets the treat, you do it again, this time it takes 5 min instead of 10. Do it again, and again and again until he is laying down with just a little bit of pressure, at this point you say the word down and apply the pressure. Once he knows the behavior he can learn the word for that behavior. With sit, you put the treat just slightly above his nose adn move it back so he basically has to sit for his nose to follow the treat, once his butt hits the ground he gets the treat, he does this a few times and then you introduce the word sit. To test his hearing have somebody behind him clap or shake keys, if he looks or tilts his ear back he can her. I suspect he is just confused rather than hard of hearing. Obedience classes sounds like an awesome idea for both you and him so that you can learn the tools to teach him properly. Remember that it is MUCH easier to teach a new trick than to unteach a wrong behavior he has learned. If in his mind "sit" means follow around your finger in a circle, you may never be able to use that word again to get him to actually "sit". Some of my agility trainers have had to get quite creative to reteach some of the dogs in our classes.
oh yeah, and if he KNOWS the trick, no treats unless he does it well, otherwise you are creating a lazy dog. He will think in his mind, "well if I can just squat instead of sit my butt all the way down I still get the treat so what's the point in the extra effort"
I would stick with the signs. I trained my (and my parents') now almost 15 year old, Hershi with both verbal and signs for every trick just out of habit. Then, she had excellent hearing. Now she is completely deaf, but because she knows signs already, she still obeys as long as she can see you. so your signs might not really seem like much now, but may come in handy many years down the road.
How old is he?
Most dogs respond much better to hand signals and body language than verbal cues. For instance, I inadvertently taught both my dogs to break a stay when I smiled; apparently I smiled right before I released them and they picked up on it. I had to go back to square one on getting them to hold with the smile, and guess what I used to make them understand? Yep, the hand signal for stay.
The only commands it's essential your dog respond verbally to are his name (by looking at you) and "come" for when he's out of eye-shot. It helps if your dog has a great "wait" OR "stay" OR 'sit" that he does at a verbal cue only, in case he is loose and a hazard (say a road) is between you and him, so you don't want him to come. However, if you use "sit" for this make sure your dog understands that "sit" means "sit where you are." Almost all dogs, unless trained carefully to understand, think that "sit" means "come up to my feet, look up at me, and then sit down." Therefore "stay" or "wait" is a better safety command. Honestly though doing a long-distance stay from a run is very advanced and most of us never really get there.
I always use hand signals too. Chances are your dog can hear just fine, but if you are curious what you can do is have someone hold your dog, go upstairs and yell "Treats!" and see what he does. You'll know right away if he can hear you or not.
I have a deaf dog in my household and they really do learn body language well. However go to the web site DEAFDOG.ORG they have all the info. you need on all of the different training methods available for deaf or hard of hearing dogs.
I did want to add that many dogs are resistant to the "down" command. Jack went through a phase where he'd refuse to "down" if there was another dog anywhere around; it's a submissive posture and they can sometimes try to avoid listening to that command.