Ayla was my least favorite at first, too. I just couldn't get past her intentionally awful English. Nothing else mattered so long as there was that.
But times change, and old barriers weaken. Chrono Trigger had always been strange in that, despite being perhaps my favorite RPG of all time, I didn't have a favorite character. I couldn't connect with any of them. Like, in Final Fantasy VI there were Celes and Gestahl. In Secret of Mana, there were Geshtar, and Krissy, and Fanha. But in Chrono Trigger, nada. Nobody! Eventually I decided I liked Lucca because of the seven main characters she was the most like me, but I didn't feel very sincere about it.
Ayla kind of snuck up on me. I had always admired her for being the strongest PC on the list, despite Crono's ridiculously large muscles. Making a woman the strongest physical fighter was a bit scandalous back then, which is probably one of the reasons they did it. It was certainly a welcome balance to the starkly sexist fact that Lucca and Marle both use ranged weapons and have horrible attack stats. But Ayla's personality never really leapt out at me all at once. She was always that gramatically challenged cave woman.
Instead, I began to notice her through my work here at the Compendium. I must've read through the script so many times I could recite it in my sleep now. The Prehistoric sections of the game are some of the most ill-defined, making it my least favorite of the time periods. In the same vein, Chrono Trigger's characterizations are not as mature as those in the Final Fantasy games, so that the most developed characters--like Frog and Marle--are actually some of the least interesting, because there isn't enough empty canvas left for the imagination to take up its share. (I suppose Magus would be an exception; he was a well-done character.) But you might say this backfired. Ayla was so severely underdone that her personality was left almost entirely to the imagination, and time proved that her colors suited me very well. So she stands today as my favorite character. I realized it at about the time that I posted as much in the "Favorite CT Character?" poll, where I made a nifty little post about why I chose Ayla.
Talk about character evolution!