He stared at me for a moment longer, and then did perhaps the first natural thing he'd ever done in his life. He caught my hand, turned, and began to run.
Was the natural thing she spoke of that he did was running away from danger/death? Since every human is born with the instinct to survive.
I was not alarmed. Because the sky-people were weak against our diseases—the Earth is so much wilder than their land—they always wrapped themselves thus.
This reminds me of The 100 where the "sky-people" went back to Earth, they were weak against certain diseases and didn't know how to survive a much more wild environment than what they were used to. They ended up having to adapt and survive by learning on their own or by watching the Grounders.
He was as dark as I inside his baggy skin. It was clear we shared ancestors, yet he spoke as if we were different species.
This shows the distance between Earth-dwellers and the sky people. They have shared ancestors but both had different upbringings, different environments, and different cultures. They're both the same yet so different due to where and how they lived. This explains the tension and wariness that both Earth-dwellers and sky people have for one another.
this is how to make pepper pot;this is how to make a good medicine for a cold; this is how to make a good medicine to throw away a child before it even becomes a child;
This quote reminds me of something my mother often mentions. Women are expected to cook, clean, and care for the ill. The last line reminds me of home remedies women did to not have a child due to the lack of access to medicine to end a pregnancy safely.
this is how you smile to someone you don't like too much;this is how you smile at someone you don't like at all;this is how you smile to someone you like completely;
This part advises the daughter that no matter what her feelings are towards someone, negative or positive, the daughter must smile and not show any signs that others may frown upon. This reminds me of the idea that women must be perfect and/or not complain.
don't swat down to play marbles - you are not a boy, you know;
This line reinforces the idea that the daughter must act like a woman and not do anything that showcases anything but that. Playing with marbles could ruin the daughter's reputation and/or show that she is not a "proper" woman.