What could cause some mac keys to type wrong symbols_

Solution
Can you give some EXAMPLES?

It's possible you simply have one of your keyboard keys toggled incorrectly, or there could be a LANGUAGE setting issue (set to French or something).
One reader suggested it might be a language issue. It was!! My computer was set
to Spanish!

Thanks so much!!!http://img.tomshardware.com/forum/uk/icones/smilies/hello.gif