Is it permissible to pray behind an imam who does not move his tongue and lips during the silent prayer and during the silent rak'ahs of the audible prayer?

It is not permissible to pray behind someone who is known not to move his tongue while reciting Al-Fatiha, because the movement of the the tongue is essential for the validity of the prayer, as stated by Maliki jurists. Some scholars, like the Shafi'is, stipulated that the reciter must hear himself. Whoever's prayer is not valid for himself, it is not permissible for someone who knows this to pray behind him.