How does a reader "get to know" a narrator?

The reader can get to know the narrator by investigating how the narrator uses words and constructs sentences, they can also see the tone the narrator is using so the reader can understand the narrators mood.

for example I've put together sentences of the same topic:

"If we humans don't do anything about pollution, the world may suffer a great deal! That's why we must work together to save the planet!"

"according to recent studies, pollution has been increasing, and is going at an unstoppable rate, there are a few ways that may be helpful that a person could do-."

see how those sentences talk about a similar topic but express a diffrent mood? you can understand the narrator based on the mood of their writing.

a low four-wheeled open carriage of a kind formerly used in russia.