For quite awhile people had to wait for most of there mail to arrive by postal workers. It could take about 4 days to a month until it arrives.
Before phones, letters and speech, there was nothing. No talk, no text. Humans/cavemen or our ancestors, had nothing of what we have today. Millions of years ago, No one knew what talking or anything was. As time went on humans have developed there ways of communication, such as cave paintings, horse back riding to deliver the message or letter. Postal services deliver the letters to people all over the world. This point in time,(2018) our phones and other mobile devices have taken up our lives with there abilities and other services that are available on phones. We send emails, text messages and so much more on our phones.