They didn't choose to. My mom was filling out my birth certificate and my older sister came into her hospital room adn jumped up on the bed, adn her pen made a stray mark. My mom didn't notice it until she got the printed version of my birth certificate. They just thought, "Oh well, we'll leave it Chloe'. It's pretty, adn I highly doubt many people are going to take the time to stop and try to pronounce it Klo-ay." So I've always been Chloe.