🚀 go-pugleaf

I have some general questions to ask of anyone who is familiar with
current practices in dealing with national character sets in Europe and
Japan.  These questions are about the characters in the contents since,
I assume, the headers will only contain standard ASCII characters to
conform to RFC822.  I am somewhat familiar with JUNET which is in use
in Japan but I have less information about practices in Europe so I 
would appreciate any information that net readers can provide.

1. What encodings are commonly in use?  Are there any that seem to be
   standard which are used between languages or are there separate ones
   for each language?

2. Does anyone use the 8th bit or are extended sets encoded through
   escape sequences so the transmitted message is always 7 bit?

3. Do sendmail programs or the mailers distinguish between mail sent to
   compatible progams and mail sent to programs which may have different
   conventions?

4. Are there any general references or articles on the above subjects?

Thanks in advance.

Bob Bundy, Interactive Systems Corp., Boulder, CO, USA