This is, hopefully, the end of the saga: the third installment of the Shakesperean scansion series. The first two can be found here:
Shakespeare's Scansion: the Sequel
I've done some comparatively extensive research and will answer my own question below as a matter of "sharing information with those eager others." Should someone find my answer unsatisfactory, or half-baked, or in some other way faulty, PLEASE don't hesitate to say so. Should someone believe they have a better one, PLEASE don't hesitate to provide it. I'm all eyes and ears. This is obviously important to me, and of some considerable interest to many others.
Okay, here goes:
Wikipedia states flatly that iambic pentameter is the most common meter in English poetry. That's a laugh. There has been very little meter, and less rhyme, in English poetry in the last eighty years or so, which is an ignominious phenomenon no matter how colorful and jolly the fig leaf is with which we try to cover it up. Bear with me.
Iambic pentameter is the meter into which everyday English speech can fit almost seamlessly. It is as natural to the English language as the Alexandrine to French or iambic tetrameter to German and Russian. (Or the Terzia Rima to Italian, but that's debatable). In spite of that, it has been absent from English-language drama for more than two centuries. Talk about continuity! There is none. An author who would want to reintroduce it in today's theatre would run into a bunch of nasty problems, some of which might even seem insurmountable.
Comparisons to Shakespeare (and Shakespeare alone, at that, even though, to the best of my knowledge, Shakespeare never claimed the monopoly on writing plays in verse) would be unavoidable. The world is full of morons who love to stir trouble and gloat while watching others, who have never harmed them in any way, suffer. But that's not the biggest problem.
The biggest problem is making one's dramatic verse sound contemporary.
Which is a monumental task, considering the fact that there is NOTHING AT ALL to build on; no templates, no patterns, no rules. Nothing! One would have to literally start from scratch. A vast ignominious versificatory void lies between us and Shakespeare's times. Have you ever seen a play by Dryden produced? Have you ever even heard of Dryden? Well, duh. Shakespeare had Marlow et al to keep him honest. Whom would today's Shakespeare have?
So how does a 21st Century playwright reclaim iambic pentameter? What's allowed and what isn't? What would the public accept as contemporary, and what would they reject as tedious imitation?
One would have to address the technical aspect first. Before one starts dithering whether he or she should, or should not, use words such as "cool," "whatever" (in the contemporary sense), "asshole," and so forth, and wonder whether he or she could get away with it, one should look at the structure of the line itself: the ultimate tool of verse drama. The Swiss army knife of the dramatic handyman.
We know (more or less) how to pronounce Shakesperean English. Sort of. Sometimes we have to bend over backwards to do it, but we do have a general idea. We sort of know that a pentametric line should consist of five feet; and each of those should consist of two syllables; and the second syllable should be stressed - for the most part. The stress can be occasionally reversed: trochaic substitution, it is (flippantly) called. The ending can be masculine (standard) or feminine (with an extra unstressed syllable at the end of the line). So far, so good.
Now, the phonetics. Here are the opening lines of Richard III by William "Our Only Hope" Shakespeare:
Now is the winter of our discontent
Made glorious summer by this sun of York;
You can see that the word "glorious" sticks out. It has three syllables. It should have two in order to fit the line. And so we use elision (rhymes with derision) to make it fit. Which is to say we combine two vowels, turning them into a single diphthong, bite the bullet, and say "glor-yes."
There are thousands upon thousands of word elided in this manner in Shakespeare.
(There are other kinds of elision he uses often, but, oddly enough, those are familiar to us and wouldn't raise any flags (i.e. offend the public ear) - thanks largely to Broadway musicals: his'ry (for history), pris'ners (for prisoners), gen'ral (for general), and so forth).
But it is the merging of two vowels into one that presents the biggest problem. For, look you, the more inquisitive, the more sincere, the better people on this here forum have informed me that not all elided syllables are equal. Specifically, one of them pointed out to me that to his ear "ceremon-yes" (for ceremonious) is okay, but "cur-yes" (for curious) is, tragically, not. Which was, and is, my impression as well. At first, I suspected that the preceding consonant ("r") was a fault. But then there's "glor-yes" (as in "glor-yes summertime by this space object in New York), which breezes by painlessly. What gives?
How is this a problem, you might ask? Simple, my dear fellow intellectuals and erudites. Should a modern playwright start bending over backwards taking advantage of every elision Shakespeare ever used, he or she might as well consider using such antiquated fake pearls as "o'er" (for over), "ere" (for before), and so forth. Which would be - stylization. Stylization is only good up to a point. An attentive audience would then have a moral right to say: "Yeah, it's kind of cute and all, but we thought this was supposed to be a CONTEMPORARY play."
And so, finally, the question is:
What words can be shortened through elision by way of merging two vowels into one? ... and what words should never be shortened in this manner? In a hypothetical contemporary play in verse?
Thank you for your time.