Simplify the following text for a Grade 14 native English-speaking person.
Original: From early in his career he collaborated with famous lyric sopranos Elisabeth Schwarzkopf and Irmgard Seefried , and the recording producer Walter Legge , issuing instantly-successful albums of lieder by Schubert and Hugo Wolf .
Simplified: From early in his career he worked with famous lyric sopranos Elisabeth Schwarzkopf and Irmgard Seefried , and the recording producer Walter Legge , producing very popular albums of lieder by Franz Schubert and Hugo Wolf .