Franz Schubert set the text of Friedrich Rückert's poem "Du bist die Ruh" in 1823. The poem title translates to "You are the Rest". I picked this piece from our anthology and then had to ask if I could still use it because it was discussed in the chapter, however, while looking over the chapter I found that the authors did not look at the piece in its entirety rather they divided it and looked at the sections that had the most obvious modal mixture chords.
In my deeper analyzation I found the very subtle use of modal mixture chords chosen to further the text painting of the piece. The first verse is set in a very standard way, with no mixture chords, only some suspensions to further the idea of peace and rest discussed in the lyrics. In the second verse, however we find a ivº43 in measure 16 and again in measures 18 and 20. It is in these three measures that the composer paired these chords with the words "pleasure and pain" and "eyes and heart". As a performer I would consider two things when beginning to approach this piece. First being that Schubert chose a minor chord to bring out the idea of pain, this is the first time a sad thought has entered this piece. Secondly, I would notice the idea of the mixture of pleasure and pain, and the mixture of eyes and heart and how he chose a mixture chord to express the idea that pain (minor) can find its way among the happiness (major).
The third verse has the same harmony as the first verse and again has no use of mixture chords because the text does not call for it. In the fourth verse however the word pain is used and therefore Schubert again chose to use a iv. The chord is then repeated in the same kind of pattern but two measures later where the listener would expect a iv they find a IV because the text changed to "may my heart be full".
The harmony of the fifth verse helps convey to the performer the sense of strength and conclusion of the piece. The use of mixture chords in measures 55, 56, and 57 set up the listener and performer for what is the climax of the piece. The fifth verse is repeated so as to further emphasis the climax. The rest used before the final line helps the performer recompose his or herself before the final statement, "Oh fill it completely". It helps draw attention to the intensity of the plea.
Schubert brilliantly uses modal mixtures as direction for how he wished this piece to be performed. His textual painting allows a listener to understand this piece, even if he or she didn't know a single word of German.