@Brus - I know it's perfectly correct, but "It is I who am wrong" is too formal for me and personally I prefer "It's me who's wrong".

If Swan is right (and he is THE authority in my field), then in the original question both are correct (as subject and object form of "you" are the same); it's simply a matter of formality. But I still prefer "is" when addressing one person.

@Brus - It's a bit late in the day, but I'm with donnahansen and EngLove on this one. If the "you" being addressed is one person, "who" refers to a singular person and takes "is"; if the "you" refers to more than one person, them it takes "are". I absolutely agree with your analogy with "It's me who ...", but with the opposite conclusion. As you yourself said earlier, "It's me who am (eg responsible for...)", doesn't sound right. And that's because nobody'd say it. "It's me who is (responsible for ...)" is the grammatically natural statement. Checking through Google books with Ngram shows absolutely no examples of "It is me who am" or "it's me who am", while finding a reasonable number of examples for the "is" variety. But I'm rather surprised you don't hear that "It's me who am ..." is ungrammatical, as you hinted at earlier.

http://books.google.com/ngrams/graph?content=It+is+me+who+am%2CIt+is+me+who+is%2Cit%27s+me+who+am%2Cit%27s+me+who+is&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=

In Practical English Usage, Michael Swan gives two possibilities for the "me" type:

It is I who am responsible (formal)
It is me that's responsible (informal) (that and who are interchangeable - WW)

And recommends a possible middle way - I'm the person who is responsible.

@jf - Don't most of us have times when we are not really sure of something and want to qualify it a little, without being judged a being "lame"? It's just a suggestion.

@providencejim - Hi. In the news today:

Roberto Mancini says Manchester United are favourites for the title - The Independent
United are title favourites - Mancini - Irish Times

Hopefully, you and I are are both reasonable speakers of English, but I'm afraid we're unlikely to find agreement on this one. Where you see a business entity making decisions, I see a group of directors sitting round a boardroom table. Here's something from the Free Dictionary:

"Usage Note: In American usage, a collective noun takes a singular verb when it refers to the collection considered as a whole, as in 'The family was united on this question' .... In British usage, however, collective nouns are more often treated as plurals."

http://www.thefreedictionary.com/collective+noun

To me, a family consists of flesh-and-blood individuals. The only time I would use singular would be when considering it as an abstract idea - "The family is the mainstay of the social system", but never when talking of a group of identifiable individuals, even if they are acting as one. There's an entertaining website called Newsroom 101, where you can do exercises based on AP style, and there wast least one question where a couple were referred to as "it". Now, that's one I can't get my head round at all.

If you're interested, there's an excellent blog devoted to these differences run by an American linguist working in Britain, and not surprisingly she has a posting on this very subject:

http://separatedbyacommonlanguage.blogspot.com/2007/07/collective-noun-agreement.html

In this post, the bloggert takes an American to task for calling this British usage of plurals "atrocious", and reminds her of the linguist's mantra:

"Different dialects are different, but that doesn't make them better or worse than your dialect!

And goes on to say, "Both AmE and BrE have 'logical' subject-verb agreement systems, they're just a bit different in the assumptions/preferences behind the."

As you say, each to their own; we're probably agreed on 95% of the language anyway. For me, the diversity of English is something to celebrate and enjoy, whether it be the differences between AmE and BrE, or between standard Englishes and dialects. I get somewhat depressed when one or other group of English users start claiming that "their's" is superior, which occasionally happens in these pages. Linguistically, it's a load of old codswallop, and there are so much more interesting things to discuss, as we've been doing here.

@providencejim - Sorry, I hadn't noticed you'd already placed the origins of "oftentimes" in the 14th century.

@Ingebiorg Nordén - And the interesting thing with your example is that the same thing would happen with "the", which would change from the shwa sound / ðə / (thuh) to stressed /ðɪ :/ (thee), the same sound as we often also use before vowels.

@hot diggedy dayum - this sort of comment would be more at home on YouTube than here, where we're used to something a bit more constructive (and informed). You complain about "different than", when "different from" is the most common expression on both sides of the Atlantic. Anyway we Brits sometimes say "different to"; I've been pulled up on these pages for using it. I think I tend to use "to" when it's followed by a "what" clause, and it's absolutely standard in BrE, but Americans don't like it much. So it's really just a case of "You say tomato", etc

And the use of "oftentimes" goes back to the 14th century, so is of English origins. Incidentally, neither are what I would understand as malapropisms, such as in "this monument has been erected by pubic subscription". And how can a malapropism be anything other than syntatical (sic), pray?

http://oald8.oxfordlearnersdictionaries.com/dictionary/different
http://www.etymonline.com/index.php?term=oftentimes
http://en.wikipedia.org/wiki/Malapropism

In any case, there are many people in Britain who don't speak Standard British English (presumably what you call "proper English") as their home language - "He were in t'pub" (Yorkshire), "That's the man what done it, ain't it?" (London), "See yous all later" (West of Scotland). So dialect is not a specifically American affair, quite the reverse in fact.

@providencejim - don't take too much notice of hot diggedy dayum's "Little Englander" comments; I imagine he's probably a Daily Mail reader.

But more interesting is your point about group nouns, such as the government, the company, the family etc. The reason we tend to use a plural verb is because we prefer to use notional agreement (aka synesis) rather than formal agreement. We usually see these institutions as groups of individuals rather than single entities. I've read somewhere (although I don't know if it's true), that in official documents, the government are always referred to as "they', so as to stress collective responsibility. We do sometimes use a singular verb when we see the group as an entity. We might say that "a new government has been elected", but that "the government are to introduce a new bill".

I know Americans are uncomfortable with this use, but it works the other way round, too. To me, sentences like "The family is coming for Christmas" or "The couple is celebrating it's (?) first wedding anniversary" sound strange and to my mind, seem illogical. It's just a different way of thinking, I suppose.

http://en.wikipedia.org/wiki/Synesis

@Hal121205 - If you're so concerned about extraneous language, why don't you just "do" a web search, like the rest of us? And why should you be so concerned to find a definitive answer? If you don't like it, you don't like it, end of. But lay off the rest of us - don't do this, don't do that! I mean, really!

@patty-c - "We shouldn't use 'and so' ". What on earth rule says that?

There's nothing wrong with "and so", unless it's repeated a lot; but that goes for any expression. And it wasn't only good enough for Pepys, as njtt says, but for a lot of others, beside.

- 'Next Boy!' said Alice, passing on to Tweedledee, though she felt quite certain he would only shout out 'Contrariwise!' and so he did. (Through the Looking Glass, by Lewis Carroll)

- He had never confided in them or shared his hopes or feelings and so they saw no marked change in his behavior - (E.L.Doctorow, Ragtime)

- Which thing when Judas perceived, he went forth to meet him, and so he smote him, and slew him - 1 Maccabees 3 (among many examples from the King James Bible)

MWDEU - "Bierce 1909 objected to 'and so, but modern books generally ignore it. It is, of course, in perfectly good use'"
http://books.google.com/books?id=2yJusP0vrdgC&pg=PA94

"And so it goes" (I'm thinking KV rather than BJ).

Yes, we'd normally use whom after a preposition, but a lot of us don't use it simply because it's the object - for me, "Who do you love?" is a lot more natural than "Whom do you love". In your examples, they could have just put the preposition to the end - "Who from?", and "Yes, but who with?". Few people use whom when the preposition is stranded like that. The purists won't like it of course, but tant pis.

In TEFL we always teach students to use whom after a preposition, but your second example is quite interesting. I think I'd also say "Yes, but a war with who?" here. But I can't really give you a reason why we it seems more natural (to me) to break the preposition rule there. Consider this dialogue:

A: Have you heard? Pam's going out with Martin.
B: (disbelieving) - She's going out with who?

I can't imagine many people using whom in that reply. The only thing I can think of is that it is something to do with the fact that who comes at the end, but I can't explain why that should make a difference.

Hi Jaxagirl - Just to defend the Queen, not that I'm a great monarchist, she does in fact use "My husband and I" absolutely correctly, as she always uses it in subject position in full sentences. Whether she says "Me and Phil are off to the races" when she's at home, I've no idea, but it would be a bit too informal for her TV addresses. The Brynne Edelsten example is interesting (and different from the Queen's), the problem being that is not a full sentence. Should we read it as short for "(This is) Geoff and I attending a gala", in which case I think it's fine, if a bit formal; or is it really "(This is a picture of) Geoff and I attending a gala", in which case "me" is more correct? I think you could argue either way.

Incidentally, it is precisely because the Queen says "My husband and I", that Brits often try to avoid similar expressions. Most of don't want to sound like the Queen. Or Hugh Grant, for that matter. I think that's also a reason that many of us try and avoid using the pronoun "one", as it is also associated with the royal family and the upper classes - although they actually use it to mean "I"or "we", rather than "you". - "One has kedgeree for breakfast and one's butler brings in the newspaper, ironed of course. Then one goes for a walk with one's corgis in one's garden."

But I go along with your main drift, and what I try and argue for in this forum is the use of natural English, rather than getting your knickers in a twist over archaic and dubious 'rules' being broken. I also agree with you that each of us should be able to make up our own minds what we say. If people don't like a word or expression etc that's in general use, it's easy enough, don't use it. But there's no need to criticise others for it.