Guys, there is no more argument that you can advance that will make you right when you say “but in Latin” or “but in primary school.”

No.

In English there is no academy so there is no authority to determine right and wrong. Justify the usage you have learned, fine. Have a bad attitude, fine. You won’t win. People say she and her just like people write centre and center. The right criterion is convention, and it is indeeed standard in the US to say this is him or this is them or so forth. In Great Britain, some regional variants argue for the subject pronoun by appealing to archaic, foreign grammar. That’s fine too. If in Great Britain some people want to say this is she and if they want to argue from false premises that copula this therefore that, let them. They’ll not change the American convention, they’ll not standardize the usage. You can explain to them al say that English isn’t based on one grammar but on several, still won’t matter to them.

Warsaw, a lot of people seem unaware of the value of propositions, and clauses are certainly part of most propositions. As a writer, I can also agree that it is very important to know your clauses. Such allows for much better punctuation at the very least. Sadly, because there are as many grammars and grammarians as there are and have been in English, we get several terms for that which is more or less the same thing. Look at a matrix clause, independent clause, main clause, superordinate clause, and so forth. Again, I stress [more or less]. While one such term may be used more by one school or grammar; or more in linguistics than teaching as a profession, my using bound relative clause (versus free relative clause) was only meant as contrast, not pedantry or arrogance. I'd definitely prefer having one term "per phenomenon" to ten terms per phenomenon, even if there are such subtle differences between their usages as there sometimes are.

Sorry for the few errors in my reply, I can't edit them. I am also an English teacher and imagine that I enjoy quibbling over English just as much as the next teacher. I'm also a writer and probably like yourself spend a lot of my time debating and learning. It's fun!

@Warsaw Will,

well, you did apply the verb to delight advisedly, and you were right to do so. I de not delight, generally, in using terms for their sake. The term diachronic opposes synchronic and is used in lexicography, among other domains. It only refers to a dictionary that records a language historically versus at present only. The OED is one such dictionary. All you have to do is ask if a term is used and you don't understand it, or consult a dictionary, of course. I didn't impose the term as some kind of "infelicity."

Also, no, a bound relative clauses was stated as such for a reason. If you go back and look, you'll see that it contrasted other kinds of relative clause. There is not merely one kind of relative clause.

Also, yes, I do explain at length concepts you yourself might be aware of. However, I take expression seriously enough that I try to account for what I say rather than expecting others to assume what is meant, which isn't their job. If you'll recall, the thread is entitled the way it is for a reason. Not that you speak for everyone in the thread, nor even the majority, but if everyone knew what a complement were I doubt the thread would have been put up in the first place. Nonetheless, it's gotten some attention over the years, and I suspect that such is partly the reason.

Finally, referential indexicality wasn't addressed to you, although I did explain what it means given that it is a term. Had you contextualized my reply, you'd have seen that it wasn't meant for you but for the person who responded after you. I entertained the possibility that their message had been intended as some kind of rebuttal to what I previously wrote of gerunds.

I hadn't intended on condescending to you.

If the latter response is meant for me, there's a linguistic concept called "referential indexicality," which broadly refers to meaning that is context-dependent, that you might like to look into. A gerund's meaning can change according to context, such as in these two examples: "I usually end up speaking to my sister when I get bored" (where speaking is not thought of as speech), and "We know little about the timing of language's emergence in our species. Unlike writing, speaking leaves no material trace, making it archaeologically invisible" (where speaking is not thought of as talking trivially).

Noscitur a sociis comes to mind...

You said: "You call “He ain’t happy” colloquial American English, to which a Londoner might reply “No, it ain’t”, well, not exclusively, at least. It seems to have developed from “an’t”, of which there are three examples in Congreve’s Love for Love (1695), my favourite being “Sea-calf! I an't calf enough to lick your chalk'd face, you cheese-curd, you.”. There are several examples of the use of “ain’t” in Dickens, and for a while it was also part of British upper class cant. In modern London dialect “ain’t” is often used in double negatives –“I ain’t never seen him”, “It ain’t none of your business”. In popular culture there was the 1970s British TV series “It ain’t half hot, Mum”, and more up to date, we have “I ain’t bovvered” (Lauren, Catherine Tait Show). While I totally agree with you about the “my variety of English is better than yours” way of thinking, which of course is linguistic nonsense, I would hate to see British English denied its claim to this particular and important corner of the language."

I suppose any serious diachronic lexicon would show that its many usages have developed independently, although I agree that by all accounts it likely developed first in England as a variation of "I am not." Your point about part of the word's originating in England (that is, orthographically) is well-received and well-made, and informative: its history deserves to be shared rather than expurgated. :)

Next you say: "It’s true that English has no academy, a fact I rejoice in, but you seem to be suggesting that for that reason descriptivism “takes home the prize” . But I’m afraid I don’t see any necessary connection between the two. Prescriptivism and descriptivism are two different ways of looking at language, and the lack of an academy didn’t stop prescriptivism ruling the roost in English grammar on both sides of the Atlantic for some two hundred years. Nor does the existence of an academy rule out a descriptive approach: the three volume Gramática Descriptiva de la Lengua Española, is published under the auspices of none other than the Real Academia Española (R.A.E), often seen as the guardians of prescriptivism in Spain."

Let's start with the fact that English is taught, the fact that any of its patterns are sometimes presumed "correct" or "incorrect," and additionally, with the fact that English is frequently taught as having grammatically justified rules and as conforming to norms. Prior to making my point, actually, I'd like first to erase your adjective necessary in "necessary connection," since I did not argue deductively and since that would otherwise misrepresent my position. Also, I'd like to point out that I didn't say: "schools, pedagogues, and self-appointed grammarians haven't prescribed," (perfect aspect). Rather, I said that because English has no language academy at present, it follows that lexicography reports native English usage without reference to prescriptive grammar(s); just as it follows that descriptivism (grammar) conforms to conventional standards rather than to any particular set of rules proposed by any particular self-appointed grammarian. With English's being made up of so many different languages and its being influenced by so many different, often conflicting grammars, I fail to see a more sensible or ethical grammar than one that reports standard English as it is used conventionally.

If English is to be taught so that learners speak and write it in a standard way, then [describing] and reporting it as it is used conventionally and in its standard ways is logically truer to those conventions and standards than reducing it to a set of given prescriptions: the conventions and standards represent much of the language as it is and has always been used; whereas, excluding pedagogical and cultural traditions, no other approach structures or has structured its conventions or standards consistently. Therefore, descriptivism not only serves as a more consistent approach to inform and justify preferred usage throughout the English language, but better communicates its conventions and standards.

In short, when people claim such things as "it IS 'this is she' and NOT 'this is her'," they do so correctly only if they appeal to any particular grammar. However, if they want to report actual standard English in either convention, their claim is false. What's more, conforming to Latin influences in grammar doesn't explain to inquiring people that any number of pertinent variations exist, and that each can be justified in different ways. A descriptive approach (as seen in lexicography) does.

"Ellipsis, gerunds and present participles – some modern grammarians are dropping the distinction between gerunds and present participles, and in EFL teaching we often refer to both as –ing forms, but seeing you mentioned them, there is no way I can see “Speaking” in your “Hi Scott” example being an ellipsis of a gerund phrase (at least not in the way gerund is understood in English grammar, i.e. as having a nominal function)."

That's easy. First, I was responding to a fellow who had tried to impose the notion onto his interlocutor that speaking had to be a noun and used in its most literal sense. I pointed out that it could well be used as a finite or non-finite present participle or a gerund as seen in a verb pattern (versus as a grammatical subject, the meaning and function of which I exemplified for contrast and which would be clear through contextualization). Second, it's not that hard to omit and simultaneously imply a verb pattern where speaking could be a gerund. "Is Scott there?" "yes (I'm), speaking," present continuous. "Is Scott there," "(by way of) speaking." :) Both of these constitute elliptical structures, the first of which is a main clause, and the second of which is a prepositional phrase. Now, of course, I'm happy to admit that nearly no one would answer a phone and imply "by way of" so as to justify the gerund. My point was that if the fellow some 1000 posts ago wanted to make people feel stupid, then all kinds of linguistic gymnastics could be exercised if to shame other people. Still, "this is she" versus "this is her" are both very well explained with elliptical clauses.

As you rightly explain about ellipsis, yes what is implied is usually so obvious that it merits being left out; whereas, leaving too much out would leave a listener to wonder. However examples like, "Where is he going later, Bill?" "To dance" (vs, "he is going to dance") instead of "Where is he going later, Bill" "dance" (where, through pragmatic knowledge on the part of the listener, "dance" refers to teaching lessons as an instructor and therefore: "to my Monday night dance lesson" instead of as it would most likely be wrongly interpreted through even the slightest remove.--I concede that this does not justify entire compound-complex sentences's being reduced to mere -ing words on a regular basis, since that would of course be ludicrous except in some form of, say, sentential phone scrabble. :-P

I have to say that a lot of the arguments for "this is she" as well as "this is her" fall quite short of the mark.

First, it is true that English is not an academic language. This means that it has no academy to prescribe rules. Instead, we have two conventions of English: British and American. There is standard English, however the argument that "this is she" is to be preferred because it is standard shows that the person arguing such doesn't understand what standard means. Standard in this context only means conforming to English that is spoken in either convention by educated natives. For example, "he ain't happpy" isn't standard English but colloquial American English; which descriptively, is still a linguistic oversimplification. Rather what is standard according to said convetion is "He isn't happy" or more formal "He is not happy."

That's it. English has no academy and therefore descriptivism indeed takes home the prize.
That said, why are some people so angry about saying "this is she" versus "this is her?" Easy. Culture. They've always learned that "this is she" is how we say such, therefore they want to argue that it must be the case. However, as can be seen in several of the posts, such people don't know how to argue logically and therefore appeal to underhand suggestions that attack outside cultures. "English originiated in Britian... therefore." "Americans don't speak English as well as the British... therefore."

The crux of the issue is merely in ellipitical clauses. When one requests to speak to someone by phone, yet does not know who has answered, the person who responds will usually answer with an elliptical clause, which omis and simultaneously implies any number of words.

For example, "Hi, is Scott there?" Response: "speaking." Here, "speaking" could be a gerund or present participle, the gerund's not at all needing to suggest "speech" in a sentence like "Speaking developed in humans over 70 thousand years ago" but can simply be part of a verb pattern (like, "I hate speaking to my little sister" where the gerund can of course be interpreted as a grammatical argument that reveals information about the subject. Non-finite verbs, however, are not meant to reveal information about the subject; whereas in the example sentence, even if the non-finite verb were uninflected: "I hate [to talk] to my sister," most educated native speakers in both conventions would agree that the person must therefore talk to their sister at least from time to time. Note, pay attention to the modal verb "must," which does not argue deductively, but inductively. ;)

That is, when the person says "speaking," what they are saying is "this is the person who you are looking for and who is speaking now." It's all boiled down to "speaking," because Scott knows that the listener's capacity to assume as an intelligent being rather than a computer is such that he will assume that such is what is meant. As well, it's simply more timely and natural to speak in such a way, among other things.

If Scott had said "this is him," then the object pronoun could be imbedded in a bound relative clause where "him" is the object argument placed in the subordinate clause, "this is him (the person) whom you seek (where "whom you seek" is implied. :) )

And, now more easily: "Is Sue there?" (asked in the third person singular, and for the sake of coherence, so used in), "yes, this is she." In this example response, "This" is the demonstrative determiner that replaces the noun (and following noun phrase) "the person" or "the person you are looking for." One more time: "Is Sue there?" Response: "The person you are looking for is she." (I know, under the American convention, the sentence "this is she," and the latest development "the person you are looking for is she" would seem immediately defective. Just bear with me. If you're used to the British convention of English, know that for some people, saying such sentences would be like petting a dog backwards). Continuging, in this final case of explored responses, we are arguing for the usage of "she" in the sentence "this is she" and therefore it behooves us to say that the demonstrative determiner "this" is the subject, and hence the copula "is" predicates a subject complement: "she" by necessity. In an elliptical clause, "who is speaking" could be interpreted as well, in "this is she... who is speaking."

For some people, the problem still remains in the last part of this explanation: "she" [isn't an object] but a subject, so why is it in the place of an object. The simple answer is that it's not an object. The long answer is that in English more broadly, syntax generally conforms to the pattern: Subject, verb, object. Hence, it might seem like "this" is the subject, "is," the verb, and therefore "her" or "me,"necessarily the object. Not so. The confusion is in the details of copulas.

Let me clarify.

A copula (or more technically, a copular verb) is a special kind of verb, of which there are not very many at all. In a lot of languages, there is only one copular verb: "To be." In English, there are a few, but the most frequently used copular verb is the same: "to be." Copula comes from Latin and only means "link" or "tie." As such, we also call such verbs "linking verbs."

It gets more complicated, but not by much. Bear with me.

A "true" linking verb is always and only a linking verb. What does a true copula or linking verb do? It connects a subject with a complement. It cannot be an action. To walk is only an action verb, therefore to walk cannot be a linking verb. To [be] (happy) isn't an action. It cannot be. Again, to be is only a linking verb.

There are some other linking verbs, but the point is twofold:
1. In English, there are only just a few "true" linking verbs, and therefore it is easy to confuse their subject complements for grammatical objects. Like, "this is she" vs "this is her."

2. Because a true linking verb is followed by a complement, and because we decided that "this"is the subject in the response "this is she," the complement is by deductive inference therefore a subject complement. Subject complements that are pronouns [replace, mirror or describe their subjects] and therefore [are so inflected].

Incidentally, "subject complement" is the door to the academic world on this very question: "This is she," or "this is her." As others have attempted and as John rightly deflected, while subject complements are in the nominative case in Latin, nominative meaning that the noun or pronoun is inflected as a subject of its verb, English is not Latin. English is English and is made up of three contending morphological histories. Germanic, Latin and Greek, along with several other influences. Because there is no academy of English, there is no universally [elected] authority of the language. That's why John used "descriptivism" so much in his responses. "The rules are only as good as what is considered right by most native, educated speakers." I added to that, however, that the problem is culture, and indeed it is. There is no doubt that many teachers use such Latin influences traditionally in teaching children how to speak English, thinking that because the grammar they teach makes sense and has been done before, it must be said way. In fact, European linguistics tends to study traditional subjects; whereas in the US, linguistics focuses on phonetics and phonology a great deal more. National educations also differ considerably between Great Britain and the US. In Great Britain, many people study Latin. Not in the US.

One of the dangers of national or traditional education systems is that when something complicated or just plain wrong is taught, it is taught to everyone. In France, for example, the national education has taught for decades that in English, the imperfect (aspect) is translated with "en train de," which is only an expression of time that means "in the process of" or "in the middle of." Result? Everytime we say something in English like "I was watching t.v. yesterday night," a lot of common French people might try to translate the -ing as "J'ai été en train de regarder la télé hier soir," which of course means something different, just as if we had said, "I was in the middle of watching t.v. last night."

Now, just imagine how different regions of the country must interact with each other on their forums about such questions :)