What is the impact of the song in Wordsworth's poem "The Solitary Reaper?"

The song in the poem is what provides the internal
reflection for the subjective experience that is so vital to the poem.  The speaker,
presumably Wordsworth, experiences what he does because of the song.  He sees the woman
working in the field.  By itself, this might be an experience in its own right, but it
is the song she sings that becomes the trigger for the speaker's moral and artistic
imagination.  The words in the song are not entirely clear to the speaker and this
lexical ambiguity is critically important.  It is through this that Wordsworth is able
to project what he thinks the song means.  The song is the vehicle that takes
Wordsworth's imagination to different parts of the world and it allows him to envision
the sadness or the "melancholy strain" that he perceives to be present.   It is the song
that allows for the subjective experience.  Only through the song is Wordsworth is able
to grasp the moment of the woman singing. The notions of "seeing into the life of
things" and that poetry is rooted in the common experiences comes from the song being
sung in the poem.