Originally posted by BruceD:
Liszt, one of the great writers of transcriptions of songs of other composers for piano solo (Beethoven, Schubert, Mendelssohn, Schumann) also wrote transcriptions of songs of Chopin. Liszt's most well-known "Liebestraum" (3rd of three) is a piano solo transcription of one of his own songs : "O lieb', o lieb' so lang du lieben kannst" to words written by F. Freiligrath.
I think the piano work takes on a new, more lyrical character in the hands of one who realizes it is a transcription of a song and who concentrates on the lyricism rather than on the virtuosity of the piece; even more so if one knows the original song, of course.
 The word "song" is used here in its strict sense, a composition for voice.