In regards to your aside, I essentially went through the opposite situation, i.e. I gradually lost my hearing as a kid (genetic condition) until I was completely deaf, and then got a bunch of surgeries which fixed the situation (until I lose everything again in about 15 years, or so I'm told).
In any case, my speech was affected in the way you describe. Most soft sounds started merging, e.g. 's', 'sh', 'tsh', etc. would all end up sounding like 'sh' coming from my mouth, and I had absolutely no idea that was the case. Similarly, I had no idea what the volume of my voice was, it'd either be really loud or really quiet, but rarely at the right level. My parents (mostly) told me I wasn't speaking properly (it took years before anybody realized I was going deaf, including myself), I ended up relying heavily on the vibrations I felt in and around my mouth/throat to correct these as much as possible.
Interesting aside to this aside, there exist implants for people who were born without a cochlea (the spiraly thing which "translates" vibrations). These implants are made of some alloy (not sure what exactly) which thankfully emulate a cochlea, but have the interesting side-effect of causing the affected people to speak with a fairly monotone and somewhat metallic voice.
In any case, my speech was affected in the way you describe. Most soft sounds started merging, e.g. 's', 'sh', 'tsh', etc. would all end up sounding like 'sh' coming from my mouth, and I had absolutely no idea that was the case. Similarly, I had no idea what the volume of my voice was, it'd either be really loud or really quiet, but rarely at the right level. My parents (mostly) told me I wasn't speaking properly (it took years before anybody realized I was going deaf, including myself), I ended up relying heavily on the vibrations I felt in and around my mouth/throat to correct these as much as possible.
Interesting aside to this aside, there exist implants for people who were born without a cochlea (the spiraly thing which "translates" vibrations). These implants are made of some alloy (not sure what exactly) which thankfully emulate a cochlea, but have the interesting side-effect of causing the affected people to speak with a fairly monotone and somewhat metallic voice.