That's almost certainly a multi-byte UTF-8 character getting interpreted as 2 single-byte characters in some other encoding.
The ability to show UTF-8 is more a problem on the client side than the server side. If you are running
vi in an
xterm, you should start the
xterm with UTF-8 support:
xterm -u8 -fn '-misc-fixed-bold-r-normal--15-140-75-75-c-90-iso10646-1'
I confess that X11 fonts are something of a mystery to me, but the font specified above has always worked for me. Perhaps I've been lucky.
If you're using a Windows machine to run your graphics, the PuTTY terminal emulator can display UTF-8. Look in the "configuration" window, "Window" item, "Translation" sub-item. The "Received data assumed to be in which character set" pull-down menu has a "UTF-8" item. Select it.