Here's the reason:
* Etymology: The word "abbreviated" comes from the Latin word "brevis," meaning "short." The prefix "ab" means "away from" or "off." So, "abbreviated" literally means "taken away from being short."
* Historical Usage: The word has been around for centuries, and over time, it developed a more specific meaning related to shortening words or phrases. This specific meaning, however, didn't change the core concept of "making something shorter."
* Linguistic quirk: Language evolves organically, and sometimes words become more complex over time, even if their meanings remain relatively simple.
In short (pun intended), "abbreviated" is a long word because of its historical development and the way language works. It's a quirk of the English language that we have to accept!