Feminine from damam; quiet -- calm, silence, still.
see HEBREW damam
H1827. demamah
דְּמָמָה noun feminine (silence) whisper (on formation compare BaNB 87) — דַקָּ֑ה דְּמָמָה קוֺל הָאֵשׁ וְאַחַר 1 Kings 19:12; אֶשְׁמָ֑ע זָקוֺל דְּמָמָה Job 4:16 a whisper and a voice, i.e. an articulate whisper (compare Di); לִדְמָמָ֑ה סְעָרָה יָקֵם Psalm 107:29 he settleth storm into whisper.