The following unedited dialogue is from a novel I'm writing (which is based on a short story I wrote a while ago):
"I hope it's not an inappropriate question," Icaro said, after hesitating for a moment. "But is it true that you don't have a soul?"
Ling stared down at her shoes, and then gave a slight nod.
Icaro's eyes widened, as if he had just seen a ghost. "How did that happen? Did you lose it somewhere?"
Ling shook her head. "I was born without one."
"But then how can you, like, be alive without a soul?"
"Mmm, to be honest, I'm not quiet sure myself." Ling said, "I just know that my body managed to keep itself functioning without one."
"But there're still some sort of physical problems, right? Is that the reason you came to the hospital?"
Ling shook her head once again. "I'm perfectly healthy. The reason I'm here is that, well, I kind of work here."
"You work in the hospital?"
Ling nodded. "Well, I guess I can't really call it a job, since I don't do much. I just sit in a room while doctors run tests on me. Nothing crazy, of course. Just simple things like blood, motor, and psychological tests. In return, they give me a monthly salary, and provide me with accommodation inside the hospital. A little room that was meant to be used by emergency doctors."
Even thought it was a bit hard to believe, it somehow made sense to Icaro. Many doctors would be very interested in a case like hers.
"The pay isn't much," Ling continued. "But since I have a place to sleep, and since I can eat at the cafeteria for free, I don't really spend that much. And the tests are mostly done in the morning. So, I have the whole afternoon, evening, and night for myself."
"Sounds like a good deal," Icaro said after giving it a thought. "But I don't know, aren't you tired of spending so much time at the hospital? You know, watching sick people all the time. The smell of hospital."
"Mmm, I think I'm used to it," Ling said. "I guess everything is tolerable once you get used to it."
Each characters has his/her own story and motivations, and I tried to keep them present while writing the dialogue.
I wonder if both characters sound the same. If so, how can I do to make them sound more "different"?