How to configure spell check permanently?

I use  :
KMail
Versione 1.12.1
Con KDE 4.3.1 (KDE 4.3.1)

While I'm using the window to compose a message in the menu bar I find the path:
Impostazioni > Controllo ortografico
where I can modify the preferred language that will work with the spell check.
This is OK and it works with the current message, but the language I
choose doesn't remain permanent, and I have to make my choice every
time I write a new message.

Is there a way to let it be permanent?

In the menu bar of the main window I do find 'Impostazioni' but not
the submenu voice 'Controllo ortografico', and choosing 'Configura
KMail' I do not find any usefull item.

Thank you in advance for your tips.

ciao
Licia