This bug was filed in the Debian BTS.
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=347149

This bug was filed for 2.10 but a lot of it still apply for 2.14 and possibly later versions.

"gnome-keyboard-properties includes the following five options for keyboard
layout (among others):

    - U.S. English
      - International (with dead keys)
    - U.S. English w/ dead keys
    - U.S. English w/ ISO9995-3
      - Eliminate dead keys

I don't really have any idea how these differ; how is "U.S. English
International (with dead keys)" different from "U.S. English w/ dead
keys"?  Does "U.S. English w/ ISO9995-3" have dead keys?  Why are these
five options grouped in three sections, instead of together in one?

Also, I know what dead keys are, but if I didn't, Gnome wouldn't tell me
(although Google will).  I don't know what ISO9995-3 is, and in this case,
Google is no help either.

A picture of the keyboard is displayed with each option, but it appears
to be the same, giving no basis for choosing one layout over another.

It would be very helpful if someone who understands how these keyboard
layouts differ renamed them in Gnome to make the choices clear.  It
would also be helpful if Gnome included an explanation of dead keys."