Bright child can't retain letter names?

I would work on one letter a week and introduce the short sound as well. Write it with crayon,paint, finger dipped in water written on paper, tracing it in bowl of rice, whatever you can think of. Finding the letter in magazines, pictures that begin with this sound cut out and make a letter collage book. Lots of review of previous letters. Have her find letters when your in the car on signs in stores. Some kids just need maturation, but given our kids backgrounds its best your having her evaluated. She's lucky to have a proactive mom.