Mum's the word Mum's the word Mum's the word is a popular English idiom. It is related to an expression used by William Shakespeare, in "Henry VI, Part 2". The word “mum” is a slanged version of momme, which was used between 1350-1400 in Middle English with very close to the same meaning: Be silent; Do not reveal "Mum's the word" means to keep silent or quiet. "Mum" is a Middle English word meaning 'silent', and may be derived from the "mummer" who acts without speaking. Note the similar English word "mime" (Old English "mīma", Latin "mimus") meaning silent actor or imitator. The
Old English phonology fronting of the open vowel to in certain cases. It also underwent vowel shifts that were not shared with Frisian: smoothing, diphthong height harmonization, and breaking. Diphthong height harmonization and breaking resulted in the unique Old English diphthongs , , , . Palatalization yielded some Modern English word-pairs in which one word has a velar and the other has a palatal or postalveolar. Some of these were inherited from Old English ("drink" and "drench", "day" and "dawn"), while others have an unpalatalized form loaned from Old Norse ( and ). Old English had four major dialect groups: Kentish, West Saxon,