I've added the name Mally to my custom dictionary in Word 2013, so it's no longer a spelling error, but Word still thinks it should be all lower-case as I should only capitalise proper nouns. Can I let Word know that this is a proper noun so it doesn't keep getting this wrong?
It should do this automatically, provided you spelt the name beginning with a capital letter when you first added it to the dictionary.
I've just tested this on my own Word 2013 installation and it works as expected
Try removing Mally and adding it again with the first letter capitalised