In the original Japanese version, Casey speaks with a Kansai dialect, which would suggest that she is from the Pokemon world's equivalent of Osaka, Goldenrod City. Adding to this is Casey's love of the Electabuzz baseball team, an analogue to the real world Osaka baseball team, the Hanshin Tigers. Not only is there a similarity in both Electabuzz and tigers being striped animals, but the Hanshin Tigers are known for having a very loyal fanbase.
Casey has been compared to Ash in his early days of Pokemon training. However, they have different styles of training, and different tastes in Pokemon.