How does one distinguish between the silent and audible prayers? And what is meant by "silent" (is it a silent reading or moving the lips without sound)? And where are the points of audibility in the audible prayer? And is the glorification (tasbeeh) in bowing, prostration, and the tashahhud silent or audible? And is the salutation (tasleem) after prayer silent or audible?

The meaning of a silent prayer is that the worshipper recites silently. The limit of silent recitation, according to the majority of scholars, is that the worshipper hears himself. Some, however, permit merely moving the tongue. As for the audible prayer, the worshipper recites audibly therein. The glorification (tasbeeh) in bowing (ruku') and prostration (sujood) is to be done silently, though a slight audible utterance is permissible. It is recommended for the Imam to make the first salutation (tasleem) more audible than the second. For the congregant (ma'moom), he should make the first salutation audible only to the extent that he hears himself and those next to him, and he should conceal the second. Some scholars hold that the person praying alone (munfarid) is like the Imam in this matter.