Etymology From Middle English momelen, a frequentative of mum (sense 3) (“silent”). Compare German mümmeln, Middle Dutch mommelen and Dutch mompelen. Perhaps related to Norwegian Nynorsk mumpa (“to gum, to chew without teeth”).
1
To speak unintelligibly or inaudibly; to fail to articulate.
Please try not to mumble so I can hear you better.
Peace, you mumbling fool.c. 1591–1595 (date written), William Shakespeare, “The Tragedie of Romeo and Ivliet”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act III, scene v]:
1 more example
A wrinkled hag, with age grown double, / Picking dry sticks, and mumbling to herself.1680, Thomas Otway, The Orphan:
Etymology From Middle English momelen, a frequentative of mum (sense 3) (“silent”). Compare German mümmeln, Middle Dutch mommelen and Dutch mompelen. Perhaps related to Norwegian Nynorsk mumpa (“to gum, to chew without teeth”).
1
A quiet or unintelligible vocalization; a low tone of voice.