OK, I was just able to use Excel to sort the MAME.xml file I use and export it. I'll try to write up a procedure below.
First, open Excel to a blank sheet. Look at the ribbon and see if the Developer menu is turned on and visible along with the other standard menus, ie Home, Insert, Page Layout, etc. If it isn't turned on, go to File, Options, Customize Ribbon. (See below) Click on the Developer option, then click on OK.
Next, you want to open the MAME.xml file using the standard Excel file selector. When Excel tries to open the file, the following panel should pop-up. Make sure you choose the third option like the pic below shows.
You will probably get the following pop-up. Ignore it and click on OK.
Excel should now display the XML Source panel on the far right of an empty sheet. See pic below. Right click on the 'header' folder so header and all the fields below it are highlighted. See pic below.
A menu will pop-up showing a 'Map element...' option. Select it and the following should pop-up. Click on OK.
Go to the bottom of the default sheet and click the + button to add another sheet to the Workbook. Activate the new sheet. Go back and right-click on the 'game' folder, select it, and the following should pop-up. Click on OK.
Go to the Developer menu, then click on the 'Import' option. Select the same MAME.xml file again. Excel should now import all the data it needs to fully define your XML schema and data.
You can now sort on any field (description, I think you said), then go to the Developer 'Export' option to write out a new file.