I am delighted to see that this thread has prospered while I was away sleeping.

I can see that I have not explained my position thoroughly. I am not a writer; I am an editor/proofreader by trade who writes, and given the proper tools I am confident I can do this job adequately. (And Liz, never fear, what I do with my day is convert techspeak to English!)

Another fact I omitted: I don't work for the tech firm in question, I work for an a small agency that has a goodly chunk of the firm's marketng communications business. The firm has enough confidence in our work to trust me to take on their style guide project (which is nearing 200 pages and has many more to go).

Unfortunately, we haven't the resources to take on more staff -- although we do have one English employee in another office whose acquaintance I plan to make before this project is completed. We've already asked the firm to supply us with the resources they use, but all they did was point me to some publicly available (and rather flawed) Web resources. I can do better than that!

Thank you very kindly for all your information. I rather imagine that, if there were one "right" resource to consult, someone would have mentioned it by now. The fact that no one has done so leads me to believe that, at least, I am not missing the obvious. And I had already included all the facts you've collectively detailed above in my guide, which gives me some additional comfort.

By the way, the words the Chambers dictionary "zeddifies" (and BTW AskOxford, the online Oxford Compact, seems to agree) include "organise" and "realise." The "-ise" spellings are listed as secondary. Do those of you who speak UK English think this is correct? I'm quite sure I've seen documents coming out of the firm's European offices that spell both of these with "-ise."

JohninKansas, I had also thought to reset the language in Word, and that helped some...but as McGrath points out, the UK English setting will accept both spellings of many words. I have no problem spotting and correcting what I know are homonyms in AmSpeak but not necessarily in UK English (tire and tire/tyre, pry and pry/prise...), but it is rather frustrating not to be able to have confidence that Word is flagging the Americanisms I don't know about.

I'm also concerned about differences that have nothing to do with spelling, examples of which include the non-use of serial commas, the addition of hyphens after prefixes in many places where we would not use them, the which/that controversy, and the different approach to the use of quotation marks. All of these are included in the guide already, and I think I understand them fairly well...the trouble is, as one American poet (give the link a minute to load; there's a splash page first) whose backside I am happy to see exiting the halls of power so eloquently put it:

As we know,
There are known knowns.
There are things we know we know.
We also know
There are known unknowns.
That is to say
We know there are some things
We do not know.
But there are also unknown unknowns,
The ones we don't know
We don't know.

- D.H. Rumsfeld