Keyboard indicator limited to four

[Avraham Hanadari]

Ubuntu by default limits the number of possible keyboard mappings to 
four. I'm a linguist and language hobbyist, and I really would like to 
have access to more. I just learned how to enable Chinese, using the 
SCIM input method. So, now I'm actually up to five. I'm sure there's a 
way to tweak some system file to increase the number.  There are many 
files which contain the word keyboard. Can anyone tell me which one I'd 
need to edit?

Many thanks, Avraham