It is simply because you are full of mental and vital activities and relations. One must get the power to quiet the mental and vital, if not at first at all times, yet whenever one wills—for it is the mind and vital that cover up the psychic being as well as the self (Atman) and to get at either one must get in through their veil; but if they are always active and you are always identified with their activities, the veil will always be there. It is also possible to detach yourself and look at these activities as if they were not your own but a mechanical action of Nature which you observe as a disinterested witness. One can then become aware of an inner being which is separate, calm and uninvolved in Nature. This may be the inner mental or vital Purusha and not the psychic, but to get at the consciousness of the inner manomaya and pranamaya purusa is always a step towards the unveiling of the psychic being. Yes, it would be better to get full control of the speech—it is an important step towards going inward and developing a true inner and yogic consciousness.

Volume: 22-23-24 [SABCL] (Letters on Yoga), Page: 639

Truth in speech and truth in thought are very important.
The more you can feel falsehood as being not part of yourself, as coming on you from outside, the easier it will be to reject and refuse it.

Volume: 22-23-24 [SABCL] (Letters on Yoga), Page: 652

I have read again the message of the yogi quoted in your letter but apart from the context nothing much or very definite can be made out of it. There are two statements which are clear enough: “In silence is wisdom"—it is in the inner silence of the mind that true knowledge can come; for the ordinary activity of the mind only creates surface ideas and representations which are not true knowledge. Speech is usually the expression of the superficial nature; therefore to throw oneself out too much in such speech wastes the energy and prevents the inward listening which brings the word of true knowledge.... “In listening you will win what you are thinking of" means probably that in silence will come the true thought-formations which can effectuate or realise themselves. Thought can be a force which realises itself, but the ordinary surface thinking is not of that kind; there is in it more waste of energy than in anything else. It is in the thought that comes in a quiet or silent mind that there is power.

“Talk less and gain power" has essentially the same meaning; not only a truer knowledge, but a greater power comes to one in the quietude and silence of a mind that, instead of bubbling on the surface, can go into its own depths and listen for what comes from a higher consciousness.

It is probably this that is meant; these are things known to all who have some experience of yoga.

Volume: 22-23-24 [SABCL] (Letters on Yoga), Page 653

The peace liberates from all dependence on outer contacts—it brings what the Gita calls the atmarati. But at first there is a difficulty in keeping it intact when there is the contact with others because the consciousness has the habit of running outwards in speech or external interchange or else of coming down to the normal level. One must therefore be very careful until it is fixed; once fixed it usually defends itself, for all outer contacts become surface things to a consciousness full of the higher peace.

Volume: 22-23-24 [SABCL] (Letters on Yoga), Page: 654

Equality is the chief support of the true spiritual consciousness and it is this from which a sadhak deviates when he allows a vital movement to carry him away in feeling or speech or action. Equality is not the same thing as forbearance,—though undoubtedly a settled equality immensely extends, even illimitably, a man's power of endurance and forbearance. Equality means a quiet and unmoved mind and vital, it means not to be touched or disturbed by things that happen or things said or done to you, but to look at them with a straight look, free from the distortions created by personal feeling, and to try to understand what is behind them, why they happen, what is to be learnt from them, what is it in oneself which they are cast against and what inner profit or progress one can make out of them; it means self-mastery over the vital movements,—anger and sensitiveness and pride as well as desire and the rest,— not to let them get hold of the emotional being and disturb the inner peace, not to speak and act in the rush and impulsion of these things, always to act and speak out of a calm inner poise of the spirit. It is not easy to have this equality in any full perfect measure, but one should always try more and more to make it the basis of one's inner state and outer movements. Equality means another thing—to have an equal view of men and their nature and acts and the forces that move them; it helps one to see the truth about them by pushing away from the mind all personal feeling in one's seeing and judgment and even all the mental bias. Personal
feeling always distorts and makes one see in men's actions, not only the actions themselves, but things behind them which, more often than not, are not there. Misunderstanding, misjudgment which could have been avoided are the result; things of small consequence assume larger proportions. I have seen that more than half of the untoward happenings of this kind in life are due to this cause. But in ordinary life personal feeling and sensitiveness are a constant part of human nature and may be needed there for self-defence, although, I think, even there, a strong, large and equal attitude towards men and things would be a much better line of defence. But for a sadhak, to surmount them and live rather in the calm strength of the spirit is an essential part of his progress.
The first condition of inner progress is to recognise whatever is or has been a wrong movement in any part of the nature,—wrong idea, wrong feeling, wrong speech, wrong action,—and by wrong is meant what departs from the truth, from the higher consciousness and higher self, from the way of the Divine. Once recognised it is admitted, not glossed over or defended,—and it is offered to the Divine for the Light and Grace to descend and substitute for it the right movement of the true Consciousness.

Volume: 22-23-24 [SABCL] (Letters on Yoga), Page: 661

To be free from all egoistic motive, careful of truth in speech and action, void of self-will and self-assertion, watchful in all things, is the condition for being a flawless servant.

Volume: 22-23-24 [SABCL] (Letters on Yoga), Page: 678

You must learn to act always from within—from your inner being which is in contact with the Divine. The outer should be a mere instrument and should not be allowed at all to compel or dictate your speech, thought or action.

Volume: 22-23-24 [SABCL] (Letters on Yoga), Page: 691

The sensations you describe in the crown of the head and the upper part of the forehead are such as one often gets when the higher consciousness or Force is trying to make an open passage through the mind for itself. So it is possibly that that is happening. As for the uneasiness or feebleness there when you talk loudly etc., that also happens at such times. It is because the concentration of energy which is necessary for the inner work is broken and the energies thrown out, exhausting the parts by two inconsistent pullings. It is better when any working is going on inside to be very quiet in speech and as sparing as possible. At other times it does not so much matter.

Volume: 22-23-24 [SABCL] (Letters on Yoga), Page: 1183

It is in the silence of the mind that the strongest and freest action can come, e.g., the writing of a book, poetry, inspired speech, etc. When the mind is active it interferes with the inspiration, puts in its own small ideas which get mixed up with the inspiration or starts something from a lower level or simply stops the inspiration altogether by bubbling up with all sorts of mere mental suggestions. So also intuitions or action, etc. can come more easily when the ordinary inferior movement of the mind is not there. It is also in the silence of the mind that it is easiest for knowledge to come from within or above, from the psychic or from the higher consciousness.

Volume: 22-23-24 [SABCL] (Letters on Yoga), Page: 1254