Speech becomes austerity only when kindness, truth, and benefit arrive in the same breath.

Read through the fullest surviving technical treatment of the verse's own terms.

Shankara and Madhusudana together give the richest surviving analysis of this line. Each of the four marks is defined with care: non-agitating as giving pain to none, true as resting on a real ground of proof, dear as pleasant to the hearer now, beneficial as producing good in the eventual outcome. The word 'and' gathers all four into one indivisible requirement, so that speech missing even one mark, however strong in the other three, is not yet the austerity being described. A model sentence shows the four working together in ordinary, caring speech.

Read honestly, where the surviving comment itself stays brief.

Ramanuja's extant gloss on this verse restates its own terms compactly: speech that stirs up no trouble, that is true, kindly, and helpful, joined to the steady practice of scriptural recitation, is called the tapas of speech. No extended, distinctively Vishishtadvaita argument survives on this particular line. Elsewhere his commentary consistently reads disciplined action as an offering referred to the Lord, and a reader may reasonably extend that same pattern to speech, but that extension belongs to the reader, not to anything Ramanuja himself wrote here.

Read where the classical source is silent outright.

Madhva offers no comment on this verse. His Gita Bhashya moves quickly through much of this chapter's cataloguing of the gunas, reserving sustained attention for verses bearing directly on the Lord's independence and the soul's dependence. A Dvaita reading of speech-discipline as itself a dependent competence, granted and exercised only by the Lord's sanction, would be a reasonable extension of his broader system. It is not something he wrote on this line, and it is offered here only as an extrapolation, clearly marked as such.

Read where the surviving comment addresses a wider block, not this verse alone.

Abhinavagupta's surviving remark treats 17.14 through 17.16 together, with the fuller comment given at 17.14. What survives there speaks of truth as an uprightness that need not hide itself, and of the dear and the beneficial as what please now and serve later, all folded into a discussion of purifying one's inner disposition. It does not descend to this verse's own fourfold structure or its recitation-discipline in their own right. A reader might extend his broader vision of speech as an expression of the self's own freedom to this verse, but that too would be an extension, not his stated word on 17.15.

Read through the one distinctive claim that does survive.

Sridhara's single surviving comment on this verse makes a real and specific point: the fourfold mark of right speech, non-agitating, true, dear, beneficial, is not a moral minimum on the way to some further practice. It is already tapas in its own right, exercised through the tongue exactly as fasting is exercised through the body. The constant recitation of the Veda is folded into this same discipline, so that both careful speech and steady study count, on his reading, as forms of the identical austerity.

Read as a practical test, independent of any single hearer's response.

Read with an eye to daily practice, Madhusudana's careful unpacking of each term becomes something close to a working checklist: does this speech give pain to none, does it rest on real knowledge, will it please the hearer now, and will it do good in the end. Framed this way, the verse is not asking you to guarantee how your words will be received, only to hold yourself to this fourfold standard before you speak, distinguishing the character words must carry from any control over their reception.