And it is also one of the signs of real art, when, when looking at it, the inner monologue stops by itself. That is, you do not need to specifically concentrate on the moment, everything happens by itself.
read Tanya O's comment and remembered Zeland. he has a thought, or rather a practice: one has to do everything consciously. that is, concentrate on the present, passing all the details through your head) for example, here I am writing this text on such and such a site, answering such and such a question. while sitting on a chair in my office. so I got up going to click the button on the kettle. pour sugar into a cup, etc.
If the meaning of stopping the dialogue is in distraction from obsessive thoughts, you can distract the central speech apparatus by trying to think in any fictional language. For example, wama ra dapa ra mata kada baka ra va ra pag ra, etc. trying to ignore meaningful associations.
Please note that the discussion of the internal dialogue is either something that has already happened, or something that has yet to be experienced, because the internal voice is the left hemisphere of the brain, and it analyzes only the work of the past or the future. Accordingly, if you concentrate as much as possible on the present moment, the inner voice will be silent, because there is no present in the left hemisphere - it is in the right, and in the right there is no inner voice. This biological focus is reflected in meditation and its principle that there is neither past nor future, everything is happening now, this is the all-present moment and this moment is you. If this does not help, then you have not focused enough on the present. This method cannot fail - you cannot concentrate enough. If you are having trouble at all, try switching differently, for example, start humming tunes to yourself, reciting poetry, playing movies in your head - whatever, just something creative.