Al-Nawawi (may Allah have mercy on him) stated regarding recitation that it is necessary to move the lips and the tongue.
Machine translationRead the Arabic original
The questioner: All right, Shaykh, another question. Al-Nawawi (may Allah have mercy on him) stated regarding recitation that it is necessary to move the lips and the tongue, and that one who recites only in his heart has no valid recitation, and according to the view that the Fatiha is a pillar, his prayer is invalid?
The Shaykh: Correct.
The questioner: I mean, is it necessary to move them?
The Shaykh: Yes.
The Shaykh: Correct.
The questioner: I mean, is it necessary to move them?
The Shaykh: Yes.
Source
www.al-albany.com
The Arabic text is copied verbatim from the original source, without any edits.