The Butterfly's Dream (1994)

This European existential drama utilizes complex symbols inspired by abstract psychological theories to explore the effects and reasons behind a young classical actor's decision to stop talking. No one knows why Massimo has vowed to stop talking. Other than speaking dialog from classical plays, Massimo refuses to say a single word. His father, a classic-literature professor believes it reflects to a disappointing love affair. His new girlfriend thinks Massimo is rebelling against his mother, a poet. A director learns of Massimo and commissions his mother to write a play about him. Though Massimo plays himself in the play, and does speak, he returns to silence when the play is finished.

Unfortunately the movie The Butterfly's Dream is not yet available on HBO Max.