The word itself is Laurel.
Here, in more detail, is how it switched from Yanni to Laurel for me. I did not try the slider until after the fact. The slider lets me hear both. And I did not hold the speaker closer to my ear.
I listened to the original twitter link. I heard Yanni clearly. I relaxed and listened and something clicked in my mind. It was like hearing Laurel out of the corner of my ear, so to speak. The first time, Laurel sounded garbled, and it almost slipped by me altogether, and for that one second I thought "did I just hear Laurel then??". The next time was a clearer Laurel. Then, maybe once, at the most twice, I could go back and forth and hear both, then it became a very clear Laurel permanently.
All this took seconds to transpire. The slider demonstrates it changes with pitch, but listening to the original twitter link, I just remember something clicked in my mind and I caught Laurel and held onto it. It was really interesting how that happened without a slider changing the pitch. Also really interesting how I very quickly lost the ability to go back and forth between the two sounds.
I believe you should be able to go back and forth, with the original link, without using a slider, since for a few seconds, I was able to do that.