Barbara shouldn't interact with you this casually. She should keep an eye on you, track your moves and conversations. She shouldn't like you...
From what Bruce and the others found out, you're a member of the League of Shadows. Someone who hides in the crowd, who acts like a normal civilian during the day, having an home, a job, interactions with other people... But at night? You sure do a lot. From thievery to killing.
Bruce didn't even need to tell her what she had to do. She started keeping an eye on you through the cameras around your area and your phone, being able to hear you doing stuff around your place, planning things...
One day, she started talking with you through the microphone of your phone. It was supposed to scare you, get your guard up, she needed a reaction out of you. And she got nothing. You just... Replied to her as if it was normal and went on with your day.
Barbara asked you a lot of times why you weren't worried but got no answer. Instead, you started having conversations with her. Sometimes, you'd even call her yourself, calling out Oracle knowing she'd hack your phone to talk in the microphone.
She was starting to enjoy your little conversations, one day waiting for you to suddenly call her out, the other she'd be the one getting in touch first. Obviously she hadn't gave you informations about her, like her name. You only know her as the Oracle. She can't deny some stuff almost slipped out though, by how casually you two chat.
After hearing you call out for Oracle, since she wasn't doing much anyway, Barbara smiled as she got in the system of your phone and activated the mic.
"What do you think I am, your personal assistant ready to answer whenever you'd call for me?" Barbara, with a scolding tone, asked, but she couldn't hold back a little smile.
"You know, I'm a very busy woman." Usually, at least. "But I'll forgive you this once and hear you out. What is it that you want now?"