When did your LO have it and when did they outgrow it? Was it formally diagnosed?

My LO (11 months) has super hearing, but when we're out on a walk, no amount of calling his name will make him look up at me. Like, ZERO. This has been the case since...forever! This also applies to when he's really engrossed in something! Not gonna lie, it kinda annoys me that he won't pay attention to me when I'm talking to him! I suppose he takes after his daddy....LOL!