Tafsir of Al-Balad 90:9

And a tongue with which he articulates what is in his conscience, and two lips with which he covers his mouth and seeks assistance for speech, eating, drinking, blowing, and other things. The singular is shafah (lip), and its origin is shafahah; the ha was dropped from it, and its diminutive is shufayhah, with the plurals shifah and shafahāt. It is among those words that are not permitted to be pluralized with the alif and ta (as shafāt), even though it contains the feminine ta, according to what is in al-Bahr.