Physics of hearing

The people who can explain physics to my ears?
I'm hard of hearing since birth. On paper my breach listening third degree.
When I have a cold, then ear is getting worse. Of my surroundings, this phenomenon no one understands.
At different times my hearing is different. Sometimes, can hear better, sometimes, when worse.
There are a small number of people that I can perceive. They have good receptive voice. One fellow I hear, and the other says barely audible (voice). The one I hear, I hear, even from a distance and wonder why I hear if I don't hear. People think that if the volume of the hearing is over, it will be heard better. But in fact, the perception of their speech will not change. When I ask what people think if I don't understand the whole sentence, but in fact just on some word there was a moment that I couldn't hear. For example, Tomorrow will be ... day or Tomorrow will be ...Rosh... day. People think I don't hear, but actually there is just such are the above points. These moments affect the sound production out of their mouths and the pronunciation of the person. People say well, but some combination of their sounds suddenly destroy themselves.
The TV has the screen settings: brightness, gamma, contrast, sharpness. Auditory tuning my ears generally arranged in some random order. I live as if the frequency with random parameters.
There are films with clear sounds, there is a strange sound simply because of some contrived settings authors and translators of works, such as cool (or maybe there are other reasons). Here at Lostfilm just a great emotional sound.
If I just listen to it, she perceived. But if I listen to the song when the man sings, I can't understand his speech, it is hammered with music and his musical voice. Even just without music sometimes the musical voice of the singer scores his perception.
On the phone I hear people say when the communication is normal, but still there are moments when someone just something said indistinctly. I often ask for someone to call me a cab, because they have the sounds at a minimum. Sometimes you have to call a taxi. I don't know what the operator says, I only know that I had to address where we are and where to go.
I remember my classmates were listening to music from my phone (without headphones). I don't know how to listen to it (though I have not heard the sound from the then phones in 2000-ies, when iPhones were not only heard, if it was near your ear). Phone is electronic sound. From the speaker on the computer or on the recorder or just the headphones is clear sound. And the voice of a man differs from its live voice, recorded on a voice recorder or a microphone, the voice becomes electronic. I would never anybody from acquaintances did not recognize on the record.
Remember playing with a classmate Amnesia. There, in the beginning the sound was terrible and I was scared. A classmate said it was the wind. I've never heard that the wind was blowing so. So I howls of the wind were heard, but they are not loud, but in the game are live. And in Diablo 3 in the main game, in the story of the first normal sound was, and then in addition made it quieter.
In the hospital disability is not given. I do not understand why. Or once I are not down, then normal, or I can communicate with people, my problem is not critical. I note that in my city I passed the audiogram. I wore headphones and were given a button. As soon as I heard the sound I had to press the button, and they determined my hearing. At the hospital they did not have professional equipment. Just had to listen to the sound in the headphones and show with your fingers the volume level. But the catch is that I don't remember sounds. I don't even remember the sound of the Russian national anthem, although I know the text. In the end, the testimony probably is confused, and they may have thought I was kidding. Not sure in all of this to end.
I don't distinguish sounds a, z, C, W, W, Sch. I can only hear either a ringing sound or hissing. I only know what they are spelling.
I don't need to talk about the obvious point that since I am hard of hearing, it follows that the range of perception of sounds I have less.
So how to explain the nature of my hearing?