Beruriah [the daughter of Reb Meir] happened upon a scholar who was studying silently. She gave him a kick, and said to him: "It is written 'established for all time and secure' (Shmuel II 23:5) - if it is 'established' in your 248 limbs, it [the Torah you learn] will be secure, but if it is not established, it will not be secure!" (Bavli, Eruvin 53b-54a)
The above passage teaches us the necessity of learning Torah out loud, even when learning alone. Part of the idea is as Beruriah expressed it: only by involving our entire body in the process of learning - with movements, vocal expression, and the like - can we truly hope to acquire our Torah in the proper manner.
Similarly, there is a story with the author of the Noda B'Yehuda, Reb Yechezkel Landau that illustrates this point. While serving as Dayan in Brody, there was a group of secularists who sought to discredit him. One of their ploys was to recruit a gentile boy and tutor him in Torah until he was beyond fluent, not only in the Torah, but the nuance, inflection, and colloquialisms of the Yeshiva community.
In other words,a flawless forgery.
Bringing this boy to the Dayan, he was tested for hours on a broad range of subjects in Torah. Halacha, Aggadah, Hashkafah, this boy knew it all and held his own.
Eventually, the Noda B'Yehuda dismissed him with a wave of his hand. "This is all meaningless. He is not Jewish."
He said it with such conviction that his detractors realized that their facade had failed. "Rabbi - how did you know?" they asked him.
Rav Landau turned to them and said "It's certainly possible for someone to have such a level of mastery in Torah. But one thing: the entire time, the boy sat there like a statue, rattling off halachas and sugyas, but not moving even once. A Jew who learns Torah cannot help but move; he'll sway and shuckle, because the vibrancy of Torah is coursing through his veins. A Jew must move when he is learning Torah!"