The Lost Civilisation of Dave

Reading an article the other day I came across the name of an ancient civilisation from Mexico called the Teotihuacan (pronounced tay'-uh-tee'-wah-kahn). Why such long names? If I ever find a previously undiscovered extinct civilisation, I'm calling them Dave.

(Actually, they were named by the invading Aztecs, who were relative newcomers at the time.)