While a lot of race horses are lunged, it isn't an "indepth course" - it's a quick step towards long-reining during the breaking process. He won't have a great idea of what verbal commands are, and you will need to rely on your body to direct him as to what you want him to do.
When I started as manager at a pre-training yard, there were 5 horses in the process of being broken. I was told they could all lunge and were all great at it. Yup, they could all gallop around like eejits in a circle all right, wouldn't call it lunging though! Back to basics, make sure YOUR body is in the right place and telling the horse what to do. By the time I was done with those 5 they all knew the verbal commands as to what I wanted them to do. Remember you tell a horse a heck of a lot with the way you carry yourself, angle yourself and direct your shoulders.
Stop for a minute, open your mind, learn. You may not agree with what I say, I may not agree with what you say but we will both learn something new.