DD1 is Sally. Technically it's a familiar form of Sarah, so it's already a nickname. Being only two syllables too you don't need to shorten it any further.
I like this, and now we are expecting another DD I do think it might be a bit odd to have a name now that needs a nickname or is long.
So, get your thinking caps on and give me some nicknames/ready-shortened names that can stand alone and go with Sally. Not all of them can, and I need more ideas!
Thanks.