I regularly switch between English and German when working on my MacBook. I recently realised that I am doing something very silly, when I write in German, I copy the text into Firefox and use the German spell checker, then copy my work back. Today I had a massive "duh" moment, when I realised that OSX has built in spell checking. Now, I am writing an email in German, and I would like to change the language of the email to German and have the spelling checked automatically instead of me having to go through each word and telling OSX that it's a German word. Is there any way to do this?