I had a tough time with Thirteen’s first words, too. She seems to be using a different (her native?) accent than I’m used to hearing from Whittaker.
Sounded like her native Northern accent to me. https://youtu.be/Ea1KEriNW7A
She’s from Yorkshire, which I think is still considered the North. Maybe we can get oojason to weigh-in. I’m glad she’s using her natural accent. I’ve watched several interviews with her this past year and it’s just one more thing I love about her. She seems quite genuine and grounded. If you’ll forgive my momentary shallowness, I also think she’s breathtaking.