I'm running MSO2000 in Win2000.  The American language dictionary is
too aggressive and despite my attempts to set all language and
regional settings, often displaces international (UK) English in
spell-checking, especially with documents that I did not author or
which were based on an old template.

I want to fool the software by copying the UK dictionary over the US
dictionary.  How do I do this?

Try renaming the dictionaries.  Append "old" or something to the US
dictionary's name, then rename the UK dictionary to have the same name
the US originally did.

Dear Spurious,

You may be seeing this problem as more difficult than it is.  The fact
that the authorship of or template for a document influences its set
language is a feature of Office, not a bug.  The idea, of course, is
that you can even work with documents in different languages -
whatever your regional settings - and also have a number of languages
(or sections set not to be checked) set within a single document.

If you need to handle an existing document with an inappropriate
language set, it is a short matter to change this:
 o use Edit | Select All to select the entire document, and then
 o set the language you desire through Tools | Language > | Set
Language... .

I trust this helps.

Carnegie

Thanks, carnegie-ga.  I tried that first.  In PowerPoint for example,
you need to change preferences for each page.  I end up making more
language corrections than spelling corrections.

Thanks too, nelson-ga.  Problem is I can't find the dictionaries. 
Does anyone know where they are or what they're named?

Dear Spurious,

Sorry about Powerpoint: aaargh!

The dictionaries appear to be in

<drive>\Program Files\Common Files\Microsoft Shared\Proof

Carnegie

Thanks again for the path, carnegie-ga.  I have found .lex and .dll
files there.  Elsewhere, under my user name, I have found my custom
dictionary .dic files.

MS has hidden the standard spellcheck dictionaries pretty deep.  They
have put them in hidden subfolders and encoded in binary files with
subtle file names.  Somebody really doesn't want me to do what I
planned to do.  So, fearing for the health of my computer, I'm going
to stop here.

Instead, I'm going to either use MS-Office setup to remove the US
dictionary, or failing that, paste common UK English spellings into
the CUSTOM.DIC custom dictionary.

So, I'll close this question and ask the Researchers for a word list
(see question id=211486).