Here's how the theme plays out in the poem:
* The speaker encounters a lone woman reaping in a field, singing a song in an unknown language. This simple act of work and song fills the speaker with a sense of awe and mystery.
* The music, even though its meaning is lost, creates a powerful emotional response. Wordsworth describes the song as "melancholy," "sad," and "sweet." The speaker is deeply moved by the music, even though he doesn't understand the words.
* The song connects the speaker to a sense of universal human experience. While the reaper's specific circumstances are unknown, her song evokes a sense of shared human emotions, such as loss, love, and longing.
* The poem emphasizes the power of music to transcend cultural and linguistic barriers. The speaker is moved by the music even though he doesn't understand the language. This suggests that music can communicate on a deeper level than language alone.
In essence, "Solitary Reaper" is a celebration of the power of music to connect us to our shared humanity and to evoke emotions that transcend our everyday lives.