In plain words
Speech that does not disturb, that is truthful, pleasant, and beneficial, together with regular recitation and study of scripture, is called tapas of speech.
Word for word
Speech which [is] not causing agitation, true, pleasant and beneficial, and also the practice of svādhyāya: [this] is called tapas of speech.
अनुद्वेगकरं वाक्यं सत्यं प्रियहितं च यत्स्वाध्यायाभ्यसनं चैव वाङ्मयं तप उच्यते
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam· bhāṣya
अनुद्वेगकरं प्राणिनाम् अदुःखकरं वाक्यं सत्यं प्रियहितं च यत् प्रियहिते दृष्टादृष्टार्थे । अनुद्वेगकरत्वादिभिः धर्मैः वाक्यं विशेष्यते । विशेषणधर्मसमुच्चयार्थः च—शब्दः । परप्रत्ययार्थं प्रयुक्तस्य वाक्यस्य सत्यप्रियहितानुद्वेगकरत्वानाम् अन्यतमेन द्वाभ्यां त्रिभिर्वा हीनता स्याद्यदि, न तद्वाङ्मयं तपः । तथा सत्यवाक्यस्य इतरेषाम् अन्यतमेन द्वाभ्यां त्रिभिर्वा विहीनतायां न वाङ्मयतपस्त्वम् । तथा प्रियवाक्यस्यापि इतरेषाम् अन्यतमेन द्वाभ्यां त्रिभिर्वा विहीनस्य न वाङ्मयतपस्त्वम् । तथा हितवाक्यस्यापि इतरेषाम् अन्यतमेन द्वाभ्यां त्रिभिर्वा विहीनस्य न वाङ्मयतपस्त्वम् । किं पुनः तत् तपः ? यत् सत्यं वाक्यम् अनुद्वेगकरं प्रियं हितं च, तत् तपः वाङ्मयम् ; यथा ‘शान्तो भव वत्स, स्वाध्यायं योगं च अनुतिष्ठ, तथा ते श्रेयो भविष्यति’ इति । स्वाध्यायाभ्यसनं चैव यथाविधि वाङ्मयं तपः उच्यते ॥ १५ ॥
In plain words
'Not causing agitation' -- to other living beings -- means simply: not causing pain. Speech that is 'true,' and 'pleasant and beneficial' -- pleasant and beneficial, that is, in matters both seen and unseen. All these qualities together -- non-agitation, and the rest -- are what qualify real speech. And that little word 'and' is there precisely to gather all these qualities together as one whole. If speech spoken to persuade someone is missing even one, or two, or all three, of truthfulness, pleasantness, benefit, or freedom from causing distress -- it simply is not verbal austerity. The same goes if speech is truthful but missing any of the other three -- still not verbal austerity. The same if it is pleasant but missing any of the other three -- still not verbal austerity. The same if it is beneficial but missing any of the other three -- still not verbal austerity. So what actually is this austerity? Speech that is true, that causes no agitation, that is pleasant, and that is beneficial, all at once -- that is austerity of speech. Like this: 'Be at peace, my child. Devote yourself to study and to yoga, and good will come to you.' And reciting the scriptures properly, exactly as prescribed -- that too is called austerity of speech.
Close to the Sanskrit
'Not causing agitation' -- of living beings -- 'not causing pain'; speech, 'true,' and 'pleasant and beneficial' -- which, in respect of what is pleasant and beneficial in visible and unseen matters. By such properties as non-agitation-causing-ness etc., speech is qualified. The word 'and' has the sense of aggregating [these] qualifying properties. Of speech employed for the purpose of convincing another, if there should be a deficiency in any one, or two, or three, of truthfulness, pleasantness, beneficialness, [and] non-agitation-causing-ness -- that is not verbal austerity. Likewise, of truthful speech, in the deficiency of any one, or two, or three, of the others, [it does not have] the state of being verbal austerity. Likewise, of pleasant speech too, [if it is] deficient by any one, or two, or three, of the others, [it does not have] the state of being verbal austerity. Likewise, of beneficial speech too, [if it is] deficient by any one, or two, or three, of the others, [it does not have] the state of being verbal austerity. What then is that austerity? That speech which is true, non-agitation-causing, pleasant, and beneficial -- that is verbal austerity; as [for example]: 'Be at peace, my child; practice study and yoga; thus your welfare will come about' -- thus. And the practice of recitation too, according to due procedure, is called verbal austerity.
▸Gītā Vāhini
“అతిభాష లేకుండుట, అనృతములాడకుండుట, చాడీలు చెప్పకుండుట, పరులను దూషించకుండుట, కఠినోక్తులాడకుండుట, మధురమైన పలుకులు, మాధవ స్మరణతో వాక్కును పవిత్రము చేయవలెను. ఇట్లు మనో వాక్కాయములను ఉత్తమమైన మార్గమున వినయోగించిన నిజమైన తపస్సనబడును.”
In plain words
“Speech must be made holy by not talking too much, not speaking untruths, not telling tales, not reviling others, not speaking harsh words, by sweet words, and by the remembrance of Mādhava. When Manas, speech and body are used in the best way like this, that is called true tapas.”