For instance communication between Roman and Persian empires with China or European explorers in America, India, Japan etc.
I am unable to speak to anything beyond your question regarding European explorers in the Americas, but for that answer I provided [this response] (https://www.reddit.com/r/AskHistorians/comments/j6tlvw/when_western_europe_arrived_in_the_new_world_how/) to that question regarding the English, which includes a great [link] (https://www.reddit.com/r/AskHistorians/comments/erm9fy/how_did_the_spanish_conquistadors_and_early/) to an answer concerning the Spanish facing the same challenge by the very knowledgeable u/TywinDeVillena.