One of my co-workers was trying to get the attention of a little girl we work with at Kids First one day.  The little girl's family speaks Spanish at home, but she has been at Kids First since she was a baby and knows English too.  This was the day we learned that she chooses to hear only what she wants to in both languages:

Co-worker: "Come here."
Child: "Huh?"
Co-worker: "Come here."
Child: "Huh?"
Co-worker: "Come here."
Child: "Huh?"
Co-worker: "AQUI."
Child: "Que?"