Which leads me to wonder--the Midwestern accent you refer to is like Britain's Received Pronunciation, right? Does the entire country have a tacit agreement as to what it sounds like? RP

Really, no, or only an overlapping general idea of what "broadcasterese" is, and no agreement on the details. Like, broadcasterese does not drop Rs; it does not insert Rs into words like wash; it does distinguish between pen and pin; but -- you know. Till recently, the big three broacasters were a Texan, a North Dakotan, and a guy from Canada. They all had noticeably not-broadcasterese accents, if subtle ones.

To bring this back on-topic, I've come to equanimity with the number of actors who cannot control their speech well enough to drop an inappropriate accent sufficiently (or add an appropriate one). I have not yet gotten over the fact that so few actors enunciate well enough for me to understand what they're saying.

I think Midwestern is sort of the neutral TV and radio-announcer dialect, so it's really more widespread than just the Midwest.

Standard American Stage English is closest to urban mid-Atlantic, regionwise. (And supposedly also Idaho, which I've heard nicknamed "the pure-vowel-state" by musical directors.)

the fact that so few actors enunciate well enough for me to understand what they're saying

This particular foreigner has no real problem understanding 98% of what actors say. How much are you not getting?

I had a question about that, too. Are you speaking about American actors?

I never understand what Benecio del Toro is saying.

eta: He may not qualify as an American actor?

cannot control their speech well enough to drop an inappropriate accent

this. Although the example I was going to give was Cary Elwes in Poison Ivy so perhaps I am asking too much of that particular film. Still I wonder why they didn't just make the character british.

I never understand what Benecio del Toro is saying.

Have you just been watching him in Usual Suspects? Because that's what he was supposed to do there.

He's often a bit of a mumblemouth, though.

Benicio Del Toro is from, like, Pennsylvania. His mushmouth is pure personality.

I don't actually sit there completely lost as to what's going on, but I mishear words on TV all the time -- a T that might be a D, or G/K, or a couple other consonant switches -- that can change meanings. I get jerked out of the story, when I find myself relying on context to understand meaning rather than relying on hearing the word right the first time. I find most Texas accents mildly mushy, e.g., and the vowel-confusion of anybody from Chicago will usually get me asking, "Wait, what?"

Have you just been watching him in Usual Suspects?

That was the first movie I thought of, but I also had some issues with Sin City.