When I say "should've", it sounds like I'm saying "should of". It doesn't sound like a "V" sound, it's closer to "F". I guess, a "soft V" sound.
"Have" also doesn't have a hard "V" sound when I say it, it's something between "V" and "F".
I write "drawer", but it sounds the same as "draw" in my speech.
Unless I am using my telephone voice, I don't pronounce the dark "L" in words such as "hall", "milk", or "hail". These words end up with a sort of "W"/half vowel sound:
"Hawh" / "Miwhk" / "Haiyowh"
I am not a linguist, that is the closest I can get to how they might sound.
I also use grammatically incorrect speech. "I seen you do it yesterday".
"What did you think of them people".
"I done it last week".
I am aware they are wrong. I only really speak like that with friends, family, partner. It just comes out naturally with them. I do speak correctly on the telephone, speaking with DD's teachers and other parents at the school, anyone I presume is "better" than me, people I don't know well, when reading out loud or reading bedtime stories to DD. I have a "posh" voice (not Queen's English posh, just more reflective of where I was raised in Surrey, I guess "posher") that I can switch into when I feel the need. Often code-switching just happens naturally.
The same way I use "innit" with friends and my DP, but wouldn't use it at parents' evening.
Speaking "properly" just doesn't flow from my brain as naturally for me. I can write it all correctly though.
I say I can write correctly, there are probably grammar mistakes in this comment.