Version:            (using KDE 4.3.2)
Compiler:          unimportant unimportant
OS:                Linux
Installed from:    Gentoo Packages

I often switch between German and English mails. I also appreciate the check-while-you-type spell checker (aka Automatic Spellchecking) of kmail. It's great!

However, every time I write an email not in the language of the current setting every word is red underlined == misspelled :(

Then I go to "Tools" / Spellchecker and invoke the Spellchecker, switch to the appropriate language, close the spell checker dialog and go on writing.

I think you can accelerate this process easily by adding a menu which lists the available languages of the installed spell checkers with an checkmark right next to it.

Someting like: 
Options
   |- Language 
      |- X English (US)
      +-   German (Germany)

Merci,

=)