Hi! I've had cats for most of my life, and currently have 30...! Each has his/her name, and each responds only to his/her name. If I call for Mr. Christmas, no other cat cares or even looks up. When I call for Gypsy or Malaika, only Gypsy or Malaika comes.
Each cat associates the sound of the name with being petted, cuddled, scratched, and generally loved, because when teaching them their name, the name was the sound I made with great frequency while petting, scratching, etc. That sound became their name - their individual "sound", identifying with something good from Daddy.
Strange to say, one cat named Tiger only comes if I call "TigerTiger". He doesn't respond to just "Tiger", it has to be repeated as if a single name...
I have only one "similar-sound" problem with 2 cats' names. One is Holiday and the other is Mayday. When I call for Mayday, Holiday comes, too. Call for Holiday and Mayday comes running. The "-day" sound confuses. Won't happen again.
Each cat is named for their personality and character, or a season during which the came to live with us. Each name tells a story about that cat. And each cat responds individually to the name given.