Question:  Is there power in speaking Scripture aloud when you are under attack by Satan?

Answer:  There is power in Scripture.  Hebrews 4:12 speaks to this:  “For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart.”    Ephesians 6 describes God’s Word as the only offensive weapon in the armor.  Therefore, the primary way we will advance is through knowing and using God’s word.

Regarding saying it aloud–I’m not sure if there is any extra power because it is said aloud.  Memorizing and applying God’s Word is the most effective way, in my opinion, to use its truths for the problems you are facing.