GUEST 07 Oct 17 - 11:45 AM (please choose a nickname): If I have been correctly informed, Schumann made a point of using only self-invented melodies (except for "iconic" tunes such as the Marseillaise if required by the context). This even applies for traditional lyrics for which a popular melody existed previously and may thus be considered a "folk song".

This piano piece ingeniously illustrates the idea of the title, but if it were actually sung, most farmers would have problems with the large ambit, more apt for an experienced singer who is neither walking home nor shouldering a scythe.

Thus any lyrics to the tune, in any language, will be apocryphal. Lovers of classical music in the USA, presumably teachers, used to be most productive in providing such lyrics, claiming to illustrate the meaning of the piece of music. In Europe many high-browers will frown on them, the main objection being that pupils thus treated may obtain a narrowed view. The lyrics offered by the OP, "With joy I sing the miracle of spring", are somewhat charming and cannot do much harm in that sense.

Using classical tunes for lyrics that do not claim to relate to the original work, such as political songs, is quite a different subject. Whoever shouts "shame!", "profanation!", or "plagiarism for lack of own ideas!", should remember that many of our most cherished folk tunes have been stolen from other contexts, including, yes, operas. What counts is the quality of the result.