Sanskrit
अनुद्वेगकरं वाक्यं सत्यं प्रियहितं च यत् । स्वाध्यायाभ्यसनं चैव वाङ्मयं तप उच्यते ॥
anudvegakaraṃ vākyaṃ satyaṃ priyahitaṃ ca yat svādhyāyābhyasanaṃ caiva vāṅmayaṃ tapa ucyate
Translation
Speech causing no annoyance, truthful, pleasant and beneficial, the practice of the study of the Scriptures, are called the austerity of speech.
Annie Besant · The Bhagavad-Gita, translated by Annie Besant (4th ed., 1922) — Wikisource · Public Domain
Explanation
Notice the qualification on satyam here: truthful speech alone isn’t enough to count as austerity, it also has to be priya-hita, pleasant and beneficial — a version of the older Indian ethical maxim that truth should be spoken kindly, not wielded as a weapon. Pairing that discipline with svādhyāya, the practice of scriptural study, makes “austerity of speech” cover both what you say to others and what you take in — an unusually balanced definition of a virtue often reduced to mere restraint.