I think it's because English spelling typically expects the "short a as in cat" (/æ/) in a word like this to be followed by a double consonant. Callie, Calleigh, Calley, Callee would all have the short a.
When there is no double consonant, we assume that the vowel is "long a" (eɪ). Caley, Caleigh, Calie, Calee would contrast with the above.
Other examples would be Amy/Amie/Amee vs. Tammy/Tammie/Tammee, or pairs like Laddie vs Lady, Cammie vs. Mamie.
I knew a girl in high schooly named Ammie pronounced Amy, and she had a lot of trouble with that. Her parents apparently had not grasped the general spelling concept. I also know a woman named Kalee prnounced Callie, and she said her mother was baffled by people who assumed it was Kaylee. "K-A-L is Cal, and E-E is "ee," so it's obviously "KAL - EE." But it isn't obvious. If it had been spelled Kallee, there would have been no confusion.
Raleigh is an exception--it's neither "Rally" nor "Raylee"--and that's unfortunately the way English spelling is, always with exceptions to the rules. We just have to memorize the exceptions.
As for the popularity of the Leigh ending, I think people like it because it looks fancy or elegant, and more definitely feminine than some of the alternatives. (If you heard of a person named Stanleigh, you'd probably assume that was a woman, or at least wonder). No real need to look farther than that
This message was edited 1/14/2025, 7:51 PM