I believe Siri and Porsche are the same person. Porsche talks about Siri like she is a real person, but i thnk she is just an imaginary friend or Porsche’s alter ego. When Porsche told Riot to stop treating her like a little kid Riot said “…I’ll start treating you older but am I talking to Porsche or Siri?” now if Siri was a completely different person then Riot would not ask that. Porsche also comments on how strangely her mom looks at her when her and Siri are having a conversation. No one in the story ever acknowledges Siri’s existence. When Riot and Porsche went to live on the reservation the Native woman never bought Siri clothes, gave her chores, or spoke of her and neither did any of the native people. One time Porsche’s boyfriend said “Who am I with today Siri, Porsche, or Ivory?” (her other alter ego). Siri is the alter ego Porsche made while she was in the detention home because she always felt so alone.