How did the first explorers communicate with the locals? Were certain methods used to learn each other's language?

by Dadikoe
CaglanT
TywinDeVillena

This very question was asked 3 days ago
https://www.reddit.com/r/AskHistorians/comments/7xodmv/how_did_explorers_communicate_with_natives_that/
There, you can find a reference to a FAQ with the answers you need.