I think this is a great example of how language rules really work. Aside from slight differences among dialects and perhaps a few edge cases, native speakers are in complete and immediate agreement about what isn’t allowed and (*!) what’s. There is complete consensus about this rule and we all follow it unconsiously - even though it takes careful analysis for us to be able to articulate exactly what the rule actually is.
The difference between this rule and the peripheral unimportant things that prescriptivists worry about is that this is a real consensus rule that we can see empirically all native speakers do follow whether highly literate or not. And this counters the prescriptivist misconception that under a descriptivist approach “anything goes”.
I think it comes back to Kilpatrick’s general guidance. I’m paraphrasing, because I read it decades ago. Read the sentence with your mind’s voice. If what you wrote doesn’t have a comfortable rhythm, rewrite it. Or, as I say, if it’s lumpy, stir it some more. I try, and sometimes fail, to avoid lumpy language.
To me, “it is what it is” is just as lumpy as “it’s what it’s.” Perhaps you can get away with it, but when I say it, is sounds like I’m badly attempting to speak French.
If you get the contraction at the end of the sentence, there’s an important noun being contracted ?
“Isn’t” is an adjective. it means the noun doesn’t exist or its false.
what’s contains the subject, the “what”. If a noun is important enough to be (very nearly, but for those little words … ) at the end, then its important enough that rules prevent it being in the contraction ? You’re going to have to accept that, and Accept that, you are !
You are absolutely correct. My native German speaking colleague once spent an entire sleepless night figuring out the rule when a German verb does or does not use the prefix ge- to form the past participle. He finally realized it was purely a matter of whether or not the first syllable of the verb is stressed (or the only syllable). Singen, gesingt, but spazieren, spaziert. He spent another sleepless night unable to discern the rule of why some adjectives become nouns by suffixing -heit and some with -keit: gesund, Gesundheit but narrish, Narrischkeit. But he never hesitated over which was correct, so there was some rule, even if he couldn’t work it out.
While -heit is the normal form of this suffix, it becomes -keit after certain adjectival suffixes. These are -bar , -ig , -isch , -lich , -sam . For example: nützlich (“useful”) + -heit → Nützlichkeit (“utility”).
Adjectives ending in unstressed -el, -er usually take -keit as well: eitel (“vain”) + -heit → Eitelkeit (“vanity”), mager (“meagre”) + -heit → Magerkeit (“meagreness”). However, there are a handful of exceptions, e.g. Dunkelheit (“darkness”), Sicherheit (“safety”).
Sometimes -ig- is added to the adjective and the suffix thus becomes -keit . This is the general rule with adjectives in -haft and -los : fehlerhaft (“faulty”) + -heit → Fehlerhaftigkeit (“faultiness”). There is also a fairly large number of other adjectives that follow this pattern: müde (“tired”) + -heit → Müdigkeit (“tiredness”). Two forms may exist for some adjectives, occasionally with a semantic distinction, e.g. Neuheit (“novelty”) versus Neuigkeit (“news”).
Cannot communicate with my late colleague. But my guess is that he was looking for a simple invariable rule, not one with exceptions. An example of such a rule would be that you use -keit after fricatives, but that leaves out -sam-. Or contuitives. But there are others. He was basically trying to understand how it was that he automatically supplied the correct form when we needed it. One of his interests was mathematical linguistics and he was trying to codify the rule.
Here is something he struck out on. He was trying to find a simple generative grammar that generated a substantial part of simple English sentences and was trying to find a rule that would generate the phrase “for John and me” rather than “for John and I”. A simple rule says you use me after a verb or preposition, but that doesn’t work here. The problem is that the word and can coordinate two (or more) nouns, adjectives, verbs, adverbs, prepositional phrases, sentential clauses, etc. Consider, “Mary works for John and I work for Alice.”
Well that should be "Mary works for John (comma) and I work for Alice.” for exactly the reason that I is not the object of the preposition. So his rule should have been use me if it’s the object of a preposition or a direct or indirect object of a verb.