Final answer:
Schubert makes each part different in a song by using different musical elements such as melody, rhythm, harmony, and lyrics. He can use higher or lower melodies, different rhythmic patterns, and harmonic progressions to create a distinction between the characters.
Step-by-step explanation:
In a song, Schubert can make each part different from the others by using different musical elements such as melody, rhythm, harmony, and lyrics. For example, he may use a higher melody line for one character and a lower melody line for another character to create a distinction between them. He can also use different rhythmic patterns or harmonic progressions to give each character's part a unique sound.
An example of this can be seen in Schubert's song 'Erlkönig,' where he depicts four different characters: the narrator, the father, the son, and the Erlkönig. The narrator's part is usually sung in a neutral and objective manner, while the father's part may have a more authoritative tone. The son's part may be sung in a higher register to depict his vulnerability, and the Erlkönig's part may have a darker and more menacing quality.
By using these musical techniques, Schubert is able to effectively portray each character's personality, emotions, and role in the song.