There's a legend about the echo, about a nymph named Echo who was sentenced by Hera, Zeus' wife, to only be able to echo the last words of others. I think the legend doesn't do the echo justice, though. Because often I'm captivated by the morphing sounds of my own echo, not others' echoes (which has implications of egoism, but it's not all about me).
I relate it to the way that we hear our voices and how they sound in the world: completely different, often eliciting cringes or shock when we hear recordings of ourselves. The sound of the voice vibrating in the skull changes the perception and sound of voice. As you speak, the voice resonates (or builds up sound and might) in your skull, mouth, and throat. However, this resonance isn't heard by others, since they only hear what is carried on the air dispelled. It gives such a comic backstory to saying that someone's a windbag, because that's honestly all that to talking to others is in physics. We exchange wind and sound, which becomes communication, language, music, rhythm, and many more things.
In some ways, our voice is only an echo of our internal thoughts. And our internal/resonant voice is only an echo heard by others. Which means that we truly are living echoes of ourselves, in the present and past. Some of the best books I've read become an "echo of the nation," or even involve wind.
Joyce quotes a little of George Byron's "On The Death Of A Young Lady," referencing the Zephyr, who is the Greek god of the wind. I find it interesting that we revel in wind so much, and the character is deciding whether his wind is worth using to write poetry:
"Hush'd are the winds, and still the evening gloom,
Not e'en a zephyr wanders through the grove,
Whilst I return, to view my Margaret's tomb,
And scatter flowers on the dust I love."