Edit Mac OS X's custom spelling dictionary

For those struggling with the American-variant spellings, there is one thing that worked for me. While editing a document, in TextEdit, for example, Control-click (or right-click, depending on the type of mouse you use) on any text, choose Spelling, then Spelling... from the sub-menu. Once the dialogue box appears, choose Australian/British/Canadian English, as desired. Once the dialogue is closed, you should have the desired result.

What if you want to have 2 languages in one? I speak Swedish. And English. Changing the spelling each time, is a bit time consuming, when you get to switch it everytime you read e-mail, talk on iChat, etc. If the red under lines from the spelling errors would dissapear at once when changing language, it would be cool, but now I have to click on each word to get it to check for the new language.

"Jon are you sure youre using a British Keyboard, that solved the issue for me, OSX automatically begins detecting queens english spellings"

Yes.

Does anyone know what the format of the actual dictionary (the one that gives definitions) is?

I'd love to add other languages to that, but amn't sure what format I need the dictionaries in or where to put them.

Finally, a way to remove typos I've inadvertantly added to the dictionary!

Jon are you sure youre using a British Keyboard, that solved the issue for me, OSX automatically begins detecting queens english spellings

Same here!

This will be very useful for me because even when I select English (UK), it still gives me American spelling suggestions.