The common phrase "letted cat out the bag" is actually a confusion of two older phrases: "let out of the bag" and "the cat is out of the bag." The spelling of "letted" is not commonly used now, but was once used for the past tense of "let." The phonetic transcription of "let" is written as /lɛt/, and the -ed suffix is pronounced as /ɪd/ or /t/ depending on the vowel preceding it. So, "letted" would be pronounced as /ˈlɛtɪd/ or /ˈlɛt/.
To "let the cat out of the bag" is an idiomatic expression that refers to the accidental or deliberate revelation of a secret, thereby exposing a hidden truth or confidential information. This phrase is commonly used to describe an act of unintentionally disclosing a surprise or private matter, often used metaphorically. The origin of this expression dates back to medieval markets, where people would often buy small live animals, like piglets, in a bag. Dishonest merchants would deceitfully substitute a more valuable or larger item, such as a cat, in place of the expected animal. If the buyer blindly accepted the bag, they would later discover the deception only when they "let the cat out of the bag." The hidden content was inadvertently exposed, and the seller's dishonesty revealed.
Over time, this idiomatic expression evolved to signify the disclosure of any hidden or carefully guarded secret or information. It emphasizes that once a secret is unintentionally or knowingly revealed, the knowledge or surprise can no longer be concealed. It serves as a cautionary tale against carelessness or dishonesty, urging individuals to be cautious and mindful of the consequences that can occur when secrets are revealed prematurely or against one's intention.