SometimesI feel like people don't understand what I'm saying even though I try to talk clearly.

Some would just nodd their head pretending they understood me, others are like say that again? Or have to stand uncomfortably close or just change the subject or quickly move along.

It's annoying. Like I was talking to these girls last week, then when I went away, I over heard one say.

"You know, I couldn't understand a word he just said."

Another one did understand a bit.

I tried recording myself, reading an article.
While listening to my voice it sometimes breaks and quite nasal, sometimes it's difficult to understand a few words, even talking loud. I've got a deviated septum so might explain the nasal sound.

With some people I talk low, despite trying to talk loud it's like the muscles or something in my voice box are tight and I can't losen it.Like everything inside tenses up automatically.
Some people it's too loud when I shouldn't be. Or deep and squeeky or sound like Mr Bean.

I am not always like that, there are some who understand me perfectly I think. Like giving directions to someone.

I've been like this for years. Before my voice went manly all those years ago, I used to be able to shout out loud, make howling wolf sounds to tease the dog or owl noises at night when owls are about...now it just tickles my throat even trying. I do wonder if being too quiet has contributed to this.