How did the oldest writing differ from our modern writing, was there anything in common?

The ancient writing was quite complex. For example, in Egypt there were hieroglyphs, which were symbolic designations. There were no vowels in the Egyptian alphabet. Such an alphabet took a long time to master. One of the first scripts that laid the foundation for most modern European languages was the Phoenician script. The Phoenicians were able to create a simple alphabet of 22 letters. Several centuries later, the Greeks borrowed it and improved it by adding vowels.