How do we know that the Reaper's song had a lasting effect on the poet?
The nightingale and the cuckoo have always been considered as nature’s best singers. The poet is so touched by the maiden’s song that he not only compares her singing to that of nightingale and cuckoo but also announces her to be a better singer than the duo.
No Nightingale did ever chaunt
More welcome notes…
A voice so thrilling ne'er was heard
In spring-time from the Cuckoo-bird,
How deep her song has touched the poet can be understood from the fact that the poet is utterly clueless as to what the song means. Yet it holds him spellbound. He longs to understand the lyrics. He says,
Will no one tell me what she sings?—
The somber and melancholic note elicits similar emotions in the poet. He surmises that the song must be about some serious or tragic subject.
Perhaps the plaintive numbers flow
For old, unhappy, far-off things,…
Some natural sorrow, loss, or pain,
Although he discovers nothing about the actual meaning of the song, he says
Whate'er the theme, the Maiden sang
As if her song could have no ending;
The poet is so bewitched by her mellifluous singing that he listens to her “motionless and still.” Not only this he makes sure that no passerby makes any noise or movement lest it may distract her and cause her to bring an unwanted early halt to her singing. So, to every passerby he urges,
Stop here, or gently pass!
That the song made an indelible mark in the poet’s mind is clearly expressed in the final couplet:
The music in my heart I bore,
Long after it was heard no more.