Schubert's Erlkonig's final measures contain many neapolitan sixth chords to add interest intensity to the ending of the dramatic piece. They are present in measures 143, 145, and 146, at the conclusion to the work and, most importantly, the most surprising and cruel part of the work.
Neopolitan sixth chords are used to extend the pre-dominant, leading to the dominant, and to give the powerful, angry, and urgent emotions to the work. These punching impact greatly helps the drama of the father's discovery that his son is dead, taken by the erlkonig.
In measure 143, the neopolitan sixth begins subtely in the beating bass chords, on the words he arrives. This increases the tension in the work and gives the word "arrives," or "erreicht" an ominous tone. It then returns in measure 145, this time more harshly with the melody prodiminately displaying the ra, arriving on the word "not" or "distress." Another fabulous text painting by Schubert. And in measure 146, the full brillance of the chord comes across with an immense impact ass the piece comes to a close, with the N6 emphasizing the word his, his being the father's arms that hold the dead child. The Neapolitan almost places the blame for the boy's death on the father, as the dad refused to listen to the boy's worries about the Erlkonig. It nearly brings the listener to tears as they image the dead boy lying in HIS father's arms...dead.
Schubert superbly placed the Neapolitan sixth chords to provide the most impact at the very dramatic ending of the piece. He certainly could have used them earlier when discussing the son's fears, but he waits until they will be of the most use.
The performance of this piece will always be somber and chilling. The words alone describe a horrific tragedy, and the steady beat of the piano, acting as a horse's gallop, increases the drama. The performers would need to bring out this intensity. The pianist should be heavy with his chords as he traverses the work to draw attention to the heaviness of the horse and the difficulty of keeping up such a speed late at night in the wind, and the singer should attempt to portray different emotions with his or her voice as narrator, young boy, and father, each with separate identities and heaviness in the voice.
In the final six measures of the work, the singer and pianst should draw attention to the Neapolitan chords and bring them out to support the horrific scene being told. Leaning on the Ab and Eb to emphasize the harsh texture of the chord and to draw out the drama from the piece. They should both use dynamics to their advantage in order to bring out the intensity. Perhaps a piano starting in measure 143, moving toward almost a pianisimo in order to make the listener move forward in their seats, straining to hear the ghastly end!