Searched: "Russian pet names," "Russian nicknames," "Russian terms of endearment." Found lots of stuff on how to make Russian names into nicknames, but nothing about non-Russian names.
I have two characters, Dmitri from Moscow and April from Oxford. They work together, and while they are not officially involved in a romantic fashion, they are very close and have acknowledged mutual crushes. Dmitri has given April a nickname in Russian, but I have no idea what this nickname might be. It should be somewhat affectionate but not overly flowery or sappy.
Can anyone help?
Edit: Okay, a little more background appears to be needed. April is a chemist in her late twenties who has been raised in a very formal environment and is still getting used to the casual-ness of life. Her hair, which used to be brown, is prematurely grey. She has a...for sake of simplicity, let's call it a pet magpie. Dmitri is middle-class-ish (his backstory is still hazy at this point) and a few years younger than April.