One who thinks words of Torah does not need to bless. Rem"a: And this is the law of one who can rule on the law without giving a reason for one's words [Ran: Chapter 1 of Shabbat and Chapter "All images" - he wrote that it is like thinking]

The Gemara objects based on what was taught in a baraita: One may not recite the Grace after Meals in his heart, inaudibly, and if he recited the blessing in that manner, he fulfilled his obligation. In this example of the rest of the mitzvot, the obligation to hear the recitation of the blessing is only ab initio. Rather, Rav Yosef’s statement must be emended. If this was said, it was said as follows; Rav Yosef said: The dispute as to whether or not a deaf person fulfills his obligation is only in the case of the recitation of Shema, as it is written: “Hear, Israel.” But regarding the rest of the mitzvot, all agree that a deaf-mute fulfills his obligation.

Rabbi Hanina, the vice-high priest said: pray for the welfare of the government, for were it not for the fear it inspires, every man would swallow his neighbor alive. R. Hananiah ben Teradion said: if two sit together and there are no words of Torah [spoken] between them, then this is a session of scorners, as it is said: “nor sat he in the seat of the scornful…[rather, the teaching of the Lord is his delight]” (Psalms 1:1); but if two sit together and there are words of Torah [spoken] between them, then the Shekhinah abides among them, as it is said: “then they that feared the Lord spoke one with another; and the Lord hearkened and heard, and a book of remembrance was written before Him, for them that feared the Lord and that thought upon His name” (Malachi 3:16). Now I have no [scriptural proof for the presence of the Shekhinah] except [among] two, how [do we know] that even one who sits and studies Torah the Holy One, blessed be He, fixes his reward? As it is said: “though he sit alone and [meditate] in stillness, yet he takes [a reward] unto himself” (Lamentations 3:28).

rather, the teaching of the LORD is his delight,
and he studies that teaching day and night.

he meditates Heb. יהגה. Every expression of הגה refers to the heart, as you say (below 19:15): “and the meditation (והגיון) of my heart”; (Isa. 33:18), “Your heart shall meditate (יהגה) in fear”; (Prov. 24:2), “For their heart thinks (יהגה) of plunder.”

The Gemara relates more of Berurya’s wisdom: Berurya came across a certain student who was whispering his studies rather than raising his voice.

She kicked him and said to him: Isn’t it written as follows: “Ordered in all things and secure” (ii Samuel 23:5), which indicates that if the Torah is ordered in your 248 limbs, i.e., if you exert your entire body in studying it, it will be secure, and if not, it will not be secure. The Gemara relates that it was similarly taught in a baraita: Rabbi Eliezer had a student who would study quietly, and after three years he forgot his studies.

Let not this Book of the Teaching cease from your lips, but recite it day and night, so that you may observe faithfully all that is written in it. Only then will you prosper in your undertakings and only then will you be successful.