From the Publisher
"Lied" ("Song") seems just like its title, as if the music could be sung. Unlike in his "Sequenze", Berio is not concerned with virtuosity here; his aim is to convey the atmosphere of more mournful, introspective, cantabile music - its rapidly repeated pitches seem to make it hesitate, stammer.
Difficulty level, roughly compared to ABRSM exam grades. 0 is beginner, 9 is advanced (beyond grade 8).