Our items are Italian place names and we use alphabetical ordering. Letters with accents appear before other letters. For example, "Cómiso" appears before "Caccamo." How can we get the correct ordering?
See:
http://www7.tau.ac.il/omeka/italjuda/items/browse?sort_field=Dublin+Core%2CTitle&page=8
I can't reproduce this. When I create items with those titles, they sort in the correct order.
Was this site upgraded from a much older version of Omeka? You might be experiencing a very old bug where the text looks fine, but is internally stored incorrectly, which messes with the proper sorting.
The site has been upgraded a few times since the original installation about three years ago.
I believe the problem affects installations from before Omeka 1.4. It certainly sounds like this is what's happening in your case. You can tell by looking in your db.ini: installations that started after 1.4 will have a "charset" line there, and that's what avoids this problem.
Basically, the text is being stored incorrectly on the MySQL side, but being transparently converted to look correct when displayed. This makes it hard to see the problem, but incorrect sorting is one of the main areas where it's apparent.
Just setting the correct "charset" line in db.ini (charset = "utf8") will fix the problem for newly-inserted data, but will also stop the transparent conversion that's currently happening, so old text with accented or international characters will look wrong.
If you have few enough special characters used, it can be a legitimate strategy to just manually fix them. If you have many, then you'd want to have the database correct them all for you (and you'd want to do this before making any changes to db.ini).
Regardless, you definitely want to make a backup of your database before doing anything.