According to Halacha, does the Sh’ma prayer have to be recited out loud? Or can it be read by oneself? I mean B’dieved, Lechatlicha it is likely preferable to verbalize it.
H. Qeriath Shem'a 2:8
צריך להשמיע לאוזנו, כשהוא קורא; ואם לא השמיע לאוזנו, יצא. וצריך לדקדק, באותייותיה; ואם לא דיקדק, יצא
One should recite the Shem'a so that his words are audible to himself. [However, even] if he does not do this, he fulfills his obligation. One must enunciate the letters clearly. [However, even] if he does not do this, he fulfills his obligation.
The Shulhan Arukh has a slightly different permutation (OH 62:3):
צריך להשמיע לאזנו מה שמוציא בפיו ואם לא השמיע לאזנו יצא ובלבד שיוציא בשפתיו
[When reading the Shem'a,] one must hear with their ears what comes out of their mouth, but if one did not hear it, they [still] fulfilled their obligation as long as they brough it out of their lips (ie. articulated it with their mouth).
The Rambam's articulation of the law leaves ambiguity about whether one may fulfill it merely by reciting it in one's mind. The SA however demands, that even in the non-ideal scenario where one cannot hear their own recitation - at the very least, it had to have in fact been verbally enunciated.