There is no cohesive American pronunciation, accent, dialect, etc. Nor is it just East Coast, West Coast, Southern, and Midwestern.
This country is physically enormous and not all of it is even contiguous. Before internet ubiquity this naturally caused the development of regional dialects (et al). Other countries have this too though our version is a little different since it’s spread out so far physically. There are many different accents in my state and it’s not one of the largest.
Also while English is the “official” language it’s not the only one commonly spoken (others vary depending largely on location) and this has an influence on speech and vocabulary.
There are at least four different versions of Spanish that have an influence on American English. At least two versions of French. We’re not even sure how many West African languages were brought here. Irish, Swedish, Hebrew, (and on and on) all varying regionally. Not to even get into the hundreds of native languages, some of which are still commonly used.
Plus English is a language compiled from other languages and has been in constant flux since Beowulf. Linguists can’t seem to universally agree on what version of English is currently being used (4th? 5th?). It’s malleability is it’s strength and it’s charm. I love how weird English is and how it’s such a moving target though I feel a little bad for those who have to learn it as a second language. Very few native speakers are truly fluent, a good argument can be made that no one is.
In the case of Americans, we’re all jumbled up linguistically but it makes sense. Given time we would probably develop a truly distinct sub-language.
Pretty sure H is supposed to be devoid of an H when spoken, some people just assume it should.
All good points, but none of it explains why your great nation and all its people can’t tell the difference between could and couldn’t, does it?
I’m with you on that one! It’s bothered me since I was a little kid. I asked adults why “we” say it that way, thus conveying the opposite of our intended meaning, and was mostly met with confused stares like I’d shown a dog a card trick.
There are things in ‘British English’ that also doesn’t make sense.
“You can’t have your cake and eat it” never made sense to me. If you have the cake, why can’t you eat it? You have it right there?
Apparently it originally was “You can’t eat your cake, and still have it”. But the other one is quicker to say or something, so that’s what we have now.
That’s the thing with language. ‘Laziness’ usually wins. Maybe not laziness, but whatever flows better. And I guess “I could care less” is another of those.
BTW apparently the Italians have a version that basically translates to “You can’t have a drunk wife, and still have a full bottle of wine”. If true, I much prefer that saying.
Obligatory David Mitchell rant:
Its a product name. They decide the pronunciation. They could spell it Qu7fg and call it ‘Dig-I-takt’. 
Now talk to me about something controversial like GIF 
ITS A HARD ‘G’ PEOPLE FUUUUUUU
Oh…and FRUSTRATED. I lose my shit when people say FUSTRATED. 
Yes, I agree with the Stephen Fry view on language. It’s something to enjoy. Unless you go for a job interview.
I find that it’s often contextual with Canadians, similar to our imperial/metric usage. I always say zed, except in my postal code where I always say zee.
as Ukrainian, i mostly pronounce Digitakt and Digitone with fricative G
(we have both, but fricative is the default)
I’ve (as a Brit) always said it like digital. But I can fully understand why many think it should be pronounced the Swedish way. However, I will continue to say rhythm rather than rrrit-ma, because I would sound like a right plonker.
Yeah, but do you say rhythm properly, like rivum?
Just look at all those letters that don’t work next to each other - what a nightmare
Ph’nglui mglw’nafh Analog R’ytm wgah’nagl fhtagn
To be fair there are lots of different accents and dialect in Britain, take this girl from Liverpool , great accent but I bet a lot of people from the states won’t have a clue what she’s saying
Duty with all of the excentuated-ness of the “T” would make you sound as if you have and extremely tightened sphincter (if you didn’t already have British accent).
As if my duty was to hold my pinky up while sipping tea when I say duty. Again, only if you were to just decide to say duty in an otherwise American accent.
In some parts of the US kids would probably just get beat up at school for saying it like that. We have to say “doodie” for safety reasons.
Plus it’s just easier to mumble and save our energy for more important stuff 
Cthulhu fhtagn!