The source mentions a 'vow of silence.' Who were the devotees known for practicing this in Sai Baba's presence, and what did it entail?

Among Sai Baba's countless devotees, very few practiced a vow of silence. Chapter 27 specifically identifies three prominent individuals who did: Dadasaheb Khaparde, Noolkar, and Butti. While most other devotees would speak freely with Baba, some even talking back without hesitation, these three demonstrated a unique and profound humility. Their practice of silence meant they would not speak in Baba's presence. Instead of engaging in conversation, they would just bow their heads before him, showcasing an indescribable modesty and reverence. Dadasaheb Khaparde, despite being a great orator, would become silent as soon as he entered the Masjid.