I do it all the time and yes the spell check is set to automatically detect.
There are few settings you have to do in syst preferences -keyboard like this.
If you need a different keyboard layout (characters) then set it up again in system preferences by adding that language so you can easy switch by clicking on the icon in the menu bar.
Not all language spelling are installed by default, so if yours is not a part of:
you can add it following this instructions: http://apple.stackexchange.com/a/11842/46541