Q: If someone takes the shahadah to become a Muslim, is it valid if he says it without sound (but with moving lips)? Or it must be in a loud enough voice to hear himself?
A: The right thing is to say it with the lips in an audible manner, though if he says by himself it will be acceptable even though it was not audible.
And Allah Ta’ala (الله تعالى) knows best.
Mufti Ebrahim Salejee (Isipingo Beach)