I read once…
“Echo as known in Greek mythology, offended the goddess Hera by keeping her in conversation, thus preventing her from spying on one of Zeus’ amours….
To punish Echo, Hera deprived her of speech, except for the ability to repeat the last words of another.
Echo’s hopeless love for Narcissus, who had fallen in love with his own image, made her fade away until all that was left of her was her voice.”
~ This is my voice, Echo