University of California Press, 1988. It is customary to provide the text of the songs in the original language with an English translation. The quality of translations varies greatly. Singing translations that appear in the music itself frequently have to sacrifice meaning to fit the rhythm of the melodic line. A good translation attempts to follow the meaning of the original text as closely as possible and may also attempt to preserve the meter and rhyme scheme of poetical works.
Many sound recordings contain texts and translations as part of their notes.
This is an excellent source for less well-known works. The library also has books of translations for songs of the standard repertory and for songs of individual composers. Texts Debussy, Claude, 1862-1918. Texts Schubert, Franz, 1797-1828. Texts Wolf, Hugo, 1860-1903.