They didnt just sound like GIs…they carried themselves like GIs. Raucous, full of bravado.
Even subtler, contrast when Winters was shot in the foot as to how he might of reacted if he were playing a Brit. As it was he acted self-deprecating like “Fuck fuck fuck, you stupid idiot, goddamnit. Moron.” All without even verbalizing it. As a Brit it would have been more “Steady on.”
I haven’t seen Band of Brothers recently, will have to look again soon. I may have mentioned already that American accents shouldn’t be that difficult for British accents, but that it’s not actually that simplistic. A British actor shouldn’t have a hard time pronouncing words the way Americans do, but there’s more to sounding American than that. You mention central PA, like other regions it’s not as simple as pronouncing a few words in a distinctive manner. Regional accents affect all of a person’s speech, the transitional sounds between words and timing of phrases in a narrow scope, while more broadly there are subtleties of speech that result naturally from speaking in that manner. I suppose one good acting ability is picking up those details to combine with an adaptable voice for a more realistic effect.
Then there’s also an interesting counter example. Brad Pitt went far off the opposite end of the scale as an American doing an Irish Traveler accent in Snatch. After complaints about characters accents being difficult to understand in a previous movie director Guy Ritchie decided to counter the criticism by creating a character that not only couldn’t be understood by the audience but also couldn’t be understood by other characters in the movie.
Vikings (the TV series) is an odd one. Australian Travis Fimmel came up with a meandering muddled fake Scandi accent, and now the continuing cast seem to be attempting a Travis caricature contest.
I’ve realized that this is a big part of the oddness of British actors playing American - you need writers who understand how to write American English as well. Even if you have an American native playing your American character, as soon as you have her “ring” someone, she sounds odd.
Really? I say that all the time, but I might be biased because I’ve lived abroad. How do you feel about “I’ll give you a jingle”?
One British phrase I find particularly amusing is “knock up.” As in my friend from Newcastle saying “I think I’ll knock up Claire tonight.” (With “knock up” meaning “drop in on.”)
Another is my colleague from Canterbury saying “I fancy a fag” as he stepped out of the office on a break. (“Fag” in this case being a cigarette.)
There’s a guy who does a lot of impressions, either Kevin Pollak or Jay Mohr, I forget which one, but they say the key to Statham is saying these six words as fast as you possibly can:
“Do you know what I mean?”
And if you want to do a Liam Neeson impression, just say ‘that’s bananers.’
Certain words trip up British actors doing American accents. I can’t think of some others off the top of my head, but ‘goddamn’ and ‘goddamnit’ usually tip me off.
The Lavender Hill Mob, one of my all-time favourites.
Correct! 
If you want bad movie accents, the accents in the 1971 British move Get Carter are the worst thing about that otherwise remarkable film. Despite being set in Newcastle-on-Tyne, only one character (played by Alun Armstrong) has the correct Geordie accent - all the rest have generic ‘northern’ accents, and Carter (Michael Caine) is a cockney.
This is not something that would happen today - see Vera for an example.
Against the thesis, I submit the “Highlander”
You’ve got a very French Christophe Lambert attempting a highland Scot accent
Contrasted by Sean Connery, who sounds like you picked him up off an Edinburgh street, playing an Egyptian by way of Spain
I guess those don’t ‘ruin’ the movie and they’re really fun to listen to, but still
Hey, ya never know, a Scotsman could have taught him English.
That’s one I disagree with. If you live 1,000 years or more and travel the world are you going to retain your original accent? A lot of people start taking on an accent after living somewhere for a short time even if they don’t realize it.
Yabbut Lambert has a French accent across centuries of in-movie time and several sequels. Sometimes a cigar is just a cigar
Still a great popcorn flick, albeit in unintentional ways sometimes
If a thing noticeably detracts from the story, it’s bad.
Hair, makeup, lighting, blouse print, traffic noise, music score, camera zooms.
Accents.
I still have trouble believing a senior policewoman would go around calling everybody “pet” and “luv.”
“Here’s to magic!” 
Including during his flashbacks to before he learned he was immortal, when he’d never left Scotland.
But everyone wants to talk about Lambert playing a Scottish Highlander with a French accent, while ignoring the time he played a Chinese God of Lightning with a French accent, in Mortal Kombat.
Don’t forget being an English nobleman raised by apes and learning English later in life from an Englishman playing a Belgian (proper credit due for the attempt at explaining the accent there!) yet still ending up with a French accent in “Greystoke”
I figure it’s the linguistic equivalent of carcinization. Hang around long enough and all accents become French eventually
Actually, if you read the original novel by Burroughs, Tarzan self-teaches himself to READ English, and, of course, grows up speaking “Ape”. But the first human language he learns is FRENCH, from French naval officer Paul d"Arnot. So Tarzan really SHOULD have a French accent.
This may be the first time they ever got that right.