If you have more than one language in your Pages document, it can be useful to set the language for individual passages so that the spell check function recognizes the words from the correct dictionary. You can also set a passage to All or None to further help spell check the document. You can find tips like this and more in my book 'My Pages' http://macmost.com/j-mypages
Where can I get your Pages Book?
Just about anywhere they sell books. Online at Amazon (http://macmost.com/j-mypages) or other stores. In any major bookstore -- of course few will stock even a small amount of computer books these days, so you may have to ask them to order it if they don't have it in stock.