Is merely moving the tongue sufficient for saying "Alhamdulillah" without any sound?

Saying "Alhamdulillah" (Praise be to Allah) verbally is sufficient as a response to the command of praising Allah and an act of compliance. This is considered an act of remembrance (dhikr), and much good and great reward are entailed by it. It is preferable for it to be uttered aloud and to be accompanied by the heart along with the tongue.