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 grammar known as "ablaut". In this form of conjugation, the stem of the word changes to indicate the tense. Verbs like this persist in modern English; for example "sing, sang, sung" is a strong verb, as are "swim, swam, swum" and "choose, chose, chosen". The root portion of the word changes rather than its ending. In Old English, there were seven major classes of strong verb; each class has its own pattern of stem changes. Learning these is often a challenge for students of the language, though English speakers may see connections between the old verb classes and their modern forms.