Rules for "about"

I came across these two exercises today:

He didn’t talk about us
Paulo talked about him

The translations provided were

Ele não falou em nós
O Paulo falou dele

Why is “em” used in the first case to express “talk about” while “de” is used in the second case for “talk about”?


@pwsteele, it’s because the verb falar can take different prepositions in Portuguese (mostly interchangeably), so there’s not one fixed way to translate “talk about”. Here’s a more detailed explanation: Falar de ou falar em? - Portuguese Questions - Practice Portuguese