Originally Posted by antheawood
I did just this on my original Kindle 3 now I have a new Kindle 3 and it looks like this setting is not an option any more.
What is your exact problem?
A) The Kindle doesn't display a dictionary definition, even though the entry exists in the dictionary.
B) The Kindle displays definitions, but doesn't use the right dictionary.
I occasionally encountered problem A when I restored the Kindle documents folder after a firmware update or when I copied a new dictionary and lots of other books to the Kindle at the same time, because the Kindle needs to some time to index the books and the dictionary. (To see the indexing status, press the home key, then press the '.' key and click the right arrow key to select search my items.)
If you have problem B, make sure that your ebooks have the correct language codes and that your home-made dictionaries have the correct input language code (many of them don't).
If all else fails restart the Kindle.