The Highland (Scottish) girl the speaker describes is celebrated as humanity's connection to nature in a sublime, spiritual sense. He notes her song's superiority but also similarity to the nigthingale's and the cuckoo-bird's, indicating that her song is a sound as natural as a bird's or the babbling of a brook. The fact that he doesn't understand her Scottish dialect makes her sound more exotic, again more like birdsong, and also allows his imagination to thrive because he can make up what she might be singing about. He considers that her song may be about "battles long ago." Thus, to the speaker, her song is potentially a link to people and places generations before. This establishes her song (and this poem itself) as a unifying link to other moments human history and/or literature. At the end of the poem, the speaker carries the music in his heart "Long after it was heard no more." The song will continue to conjure thoughts of human nature and humanity in nature. Thus, one of the enduring qualities of humanity is the imaginative ability; how a song or poem can stay with you and continue to spark thoughts of nature and human experience throughout history.