Never. This sounds as if you are telling someone to Die. If your name is Diane or Diana, go by Dee or Dede.
― Anonymous User 9/26/2015
-3
This is my friend's nickname for Diana. In primary school, she used to get teased a lot, with children always saying something along the lines of: 'Die Di!'. Immature children ruin this as a name, so it would be better to use Diane or Diana instead of just Di, and call them Di. Also, Di doesn't sound very good on a grown woman.
― Anonymous User 6/21/2011
3
Never just call your child "Di". It looks incomplete, plain. It's best used as a nickname for Diane or Diana.