over the years norman expanded her talent into less familiar areas. in 1988 she sang a concert performance of poulenc's one-act opera "la voix humaine" ("the human voice"), based on jean cocteau's 1930 play of the same name. during the 1980s and early 1990s, norman produced numerous award-winning recordings, and many of her performances were televised. in addition to opera, many of norman's recordings and performances during this time focused on art songs, lieder, oratorios, and orchestral works. her interpretation of the "four last songs" is especially acclaimed. its slow tempo is controversial, but the tonal qualities of her voice are ideal for these late works of the romantic german lieder tradition.