origin of echo - what we always wanted to know

In Greek mythology, Echo was a nymph who loved her own voice.

Zeus, the King of the Olympians, was known for his many love affairs. Sometimes the young and beautiful Nymph Echo would distract and amuse his wife Hera with long and entertaining stories, while Zeus took advantage of the moment to ravish the other mountain nymphs. When Hera discovered the trickery she punished the talkative Echo by taking away her voice, except in foolish repetition of another's shouted words. Thus, all Echo could do was repeat the voice of another.

Echo fell in love with a vain youth named Narcissus. One day when Narcissus was out hunting stags, Echo stealthily followed the handsome youth through the woods, longing to address him but unable to speak first. When Narcissus finally heard footsteps and shouted "Who's there?", Echo answered "Who's there?" And so it went, until finally Echo showed herself and rushed to embrace the lovely youth.
He pulled away from the nymph and vainly told her to leave him alone. Narcissus left Echo heartbroken and she spent the rest of her life in lonely glens, pining away for the love she never knew, until only her voice remained.