Is it sufficient in silent recitation to move the tongue and lips without sound, while articulating the letters correctly, or does prayer become void by doing so?

Scholars have differed regarding the minimum limit for the required inaudible recitation (sirr): The majority of scholars hold that it is for the worshiper to make himself hear his recitation, unless there are impediments, and this is the more cautious opinion. The Maliki school and Ibn Taymiyyah are of the view that it is sufficient to pronounce the letters from their proper articulation points and to move the tongue and lips with them, even if the worshiper does not hear himself. An ordinary person may follow whichever scholar he trusts among the people of knowledge.