A tongue twister is a phrase that is designed to be difficult to articulate properly, and can be used as a type of spoken (or sung) word game. Additionally, they can be used as exercises to improve pronunciation and fluency. Some tongue twisters produce results that are humorous (or humorously vulgar) when they are mispronounced, while others simply rely on the confusion and mistakes of the speaker for their amusement value. Types of tongue twisters Some tongue twisters rely on rapid alternation between similar but distinct phonemes (e.g., s and sh ), combining two different alternation patterns, familiar constructs in loanwords, or other features of a spoken language in order to be difficult to articulate. For example, the following sentence was said to be "the most difficult of common English-language tongue twisters" by William Poundstone. These deliberately difficult expressions were popular in the 19th century. The popular "she sells seashells" tongue twister was originally published in 1850 as a diction exercise. The term tongue twister was first applied to this kind of expressions in 1895. "She sells seashells" was turned into a popular song in 1908, with words by British songwriter Terry Sullivan and music by Harry Gifford. According to folklore, it was said to be inspired by the life and work of Mary Anning, an early fossil collector. However, there is no evidence that Anning inspired either the tongue twister or the song. Another well-known tongue twister is "Peter Piper": Many tongue twisters use a combination of alliteration and rhyme. They have two or more sequences of sounds that require repositioning the tongue between syllables, then the same sounds are repeated in a different sequence. An example of this is the song "Betty Botter" (): There are also twisters that make use of compound words and their stems, for example: The following twister won a contest in Games Magazine in 1979: Some tongue twisters take the form of words or short phrases which become tongue twisters when repeated rapidly (the game is often expressed in the form "Say this phrase three (or five, or ten, etc.) times as fast as you can!"). Examples include: Toy boat Cricket critic Unique New York A proper copper coffee pot Red leather, yellow leather Irish wristwatch, Swiss wristwatch Peggy Babcock Some tongue twisters are used for speech practice and vocal warmup: Tongue twisters are used to train pronunciation skills in non-native speakers: Other