Persephone probably could learn signs for things like come, or down, the way that Blue is accustomed to using body language as well as English for those commands to dogs, but she'd almost certainly pretend she didn't know. It's much easier for her having trained Blue into feeding her at the same time of day and knowing when she wants to be touched.

"I'm sorry I missed you!" Blue says, smiling and takes a seat with a little bit of a question. "Thank you. People don't always ..." She doesn't recall the sign for believe so she spells it out. "It's my real name."

"Are you new here?" She doesn't know everyone here by a long shot but she's gotten fairly good at recognizing when she's never seen a person before. The people like them who are out of place and time tend to congregate, a little.