Why does Tobi's voice change?

Tobi's voice changes due to the use of a special vocal mask that alters his speech, reflecting his dual identity and the thematic complexity of his character in "Naruto." Initially, his voice is high-pitched and playful, representing his alter ego as a seemingly incompetent subordinate. However, when he reveals his true identity as Obito Uchiha, his voice deepens and becomes more serious, signifying his transformation and the weight of his past. This shift in voice effectively emphasizes the duality of his character and the evolution of his motivations throughout the series.