Imogen didn't feel right calling the Mandalorian "Mando", it felt like when someone called her "girl" or "human"-disrespectful. So she decided to call him pet names, "honey" or "dear" or whatever the mood of the day was.
I was born a slave. I'm used to being traded and sold. The universe seems to be on my side because I'm unnaturally lucky. That's how I became the Mandalorian's slave and how I left Jakku.