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 well, and was best considered an allophone of , occurring only after a nasal or when geminated. But after became word-initially in Old English, it makes sense to consider the stop the basic form and the fricative the allophone. The evidence for the allophone after front vowels is indirect, as it is not indicated in the orthography. Nevertheless, the fact that there was historically a fronting of to and of to after front vowels makes it very likely. Moreover, in late Middle English, sometimes became (e.g. "tough", "cough"), but only after back vowels, never after front vowels. This is explained