Some words in Portuguese depend on the perspective of the speaker and the listener — that is, they depend on the point of view of the people involved in the conversation.
See some perspective-based words below the image:

IR x VIR
ir: movement away from the speaker
vir: movement toward the speaker

Imagine that Roberto, a Mexican who is in Mexico, is talking on the phone with teacher Giselle, who is in Brazil. The dialogue is:
Giselle: Oi! Quando você VEM pro Brasil? (Giselle uses vir because she is currently in Brazil.)
Roberto: Eu VOU próximo ano. (The student uses ir because he is not in Brazil.)
Roberto: E você, quando vai VIR pro México? (The student uses vir because he is in Mexico.)
Giselle: Por enquanto, eu não tenho planos de IR. (Giselle uses ir because she is in Brazil, not in the student’s country.)

TRAZER x LEVAR
levar → take something away from the speaker
trazer → bring something toward the speaker

Another dialogue:
Giselle: Você pode TRAZER os livros aqui na escola? Esqueci os meus em casa.
Rebeca: Claro que posso! À tarde vou LEVAR eles pra você. (The books were at Rebeca’s house. If she’s leaving the books with Giselle, she’s moving away from them.)

Aqui x Aí
aqui → where the speaker is
aí → where the listener is

Giselle: Tudo bem AÍ no México?
Roberto: Sim, tudo bem AQUI. E AÍ no Brasil?
Giselle: AQUI no Brasil está muito quente.

Nasalization

Nasalization