Wordsworth's speaker is wandering in the Scottish highlands one day when he a spots a "Highland Lass" working all alone, reaping grain in a field. He is riveted by the beautiful and melancholy song she sings as she works. He describes the valley where she reaps as "overflowing with the sound."
The speaker describes her song as more beautiful that the "chaunt" of a nightingale or the notes of the cuckoo bird. He romanticizes these birds by imagining them in exotic locales, the nightingale "among Arabian sands," the cuckoo even farther north than the highlands, in the Hebrides. By romanticizing these creatures, Wordsworth also romanticizes the Highland lass. She, too, is a beautiful, wild creature of nature.
This is a paradigmatic or model Wordsworth poem that exemplifies some of the main traits of the Romantic movement as well as the hallmarks of Wordsworth's poetry. First, in a reversal of centuries of literature depicting poor rural figures as clowns or using them simply as scenic background, he treats this laboring woman with great respect and foregrounds her. Rather than ridicule her, he exalts her for her sublime song.
Second, the poem celebrates nature by comparing the song of this young woman to the song of birds, and does so in a way that elevates both nature and the woman. Finally, the poem ends with the idea that this simple scene can live on in memory, providing joy and solace.