Language Tautology

Tautology and pleonasm are not consistently differentiated in literature. Like pleonasm, tautology is often considered a fault of style when unintentional. Intentional repetition may emphasize a thought or help the listener or reader understand a point. Sometimes logical tautologies like "Boys will be boys" are conflated with language tautologies, but a language tautology is not inherently true, while a logical tautology always is.

The word was coined in Hellenistic Greek from ταὐτός ('the same') plus λόγος ('word' or 'idea'), and transmitted through 3rd-century Latin tautologia and French tautologie. It first appeared in English in the 16th century. The use of the term logical tautology was introduced in English by Wittgenstein in 1919, perhaps following Auguste Comte's usage in 1835.

• "Only time will tell if we stand the test of time", from the Van Halen song "Why Can't This Be Love"
• "After we change the game it won't remain the same." from the Blackalicious song "Blazing Arrow"
• "That tautological statement has repeated an idea."
• "There once was a fellow from Perth
  Who was born on the day of his birth.
  He got married, they say
  On his wife's wedding day,
  And died when he quitted the earth."
• "...A forget-me-not, to remind me to remember not to forget." from the Benny Hill song "My Garden of Love"
• "Assless chaps" – chaps by definition are separate leg-coverings; a similar garment joined at the seat would instead be called a pair of trousers.
• "...und wenn sie nicht gestorben sind, dann leben sie noch heute" (and if they have not died, then they are still alive today), traditional German formula to end a fairy tale (like "they lived happily ever after").
• "Former alumni" – alumni means those who are former members of an institution, group, school etc.
• "Wandering planet" – the word planet comes from the Greek word 'πλανήτης (planḗtēs), which itself means "wanderer".
• "If you know, you know", a common English phrase.
• "What's for you won't go by you", a Scottish proverb that is tautological
• "Örökrangadó derby", the name of a football match contested between MTK Budapest and Ferencváros in Hungary. The name literally translates as "Derby Derby" in Hungarian.

Abbreviations whose last word is often redundantly repeated.

Intentional repetition of meaning intends to amplify or emphasize a particular, usually significant fact about what is being discussed. For example, a gift is, by definition, free of charge; using the phrase "free gift" might emphasize that there are no hidden conditions or fine print (such as the expectation of money or reciprocation) or that the gift is being given by volition.

This is related to the rhetorical device of hendiadys, where one concept is expressed through the use of two descriptive words or phrases: for example, using "goblets and gold" to mean wealth, or "this day and age" to refer to the present time. Superficially, these expressions may seem tautological, but they are stylistically sound because the repeated meaning is just a way to emphasize the same idea.

The use of tautologies, however, is usually unintentional. For example, the phrases "mental telepathy", "planned conspiracies", and "small dwarfs" imply that there are such things as physical telepathy, spontaneous conspiracies, and giant dwarfs, which are oxymorons.

Parallelism is not tautology, but rather a particular stylistic device. Much Old Testament poetry is based on parallelism: the same thing said twice, but in slightly different ways (Fowler describes this as pleonasm). However, modern biblical study emphasizes that there are subtle distinctions and developments between the two lines, such that they are usually not truly the "same thing". Parallelism can be found wherever there is poetry in the Bible: Psalms, the Books of the Prophets, and in other areas as well.

• Bilingual tautological expressions – Redundancy in linguistic expression
• Figure of speech – Change of the expected pattern of words
• Grammar – Structural rules of a language
• Hyperbole – Rhetorical device
• Lapalissade – An utterly obvious truism or tautology, with comical effect
• List of tautological place names – Toponyms composed of synonyms
• No true Scotsman – Informal logical fallacy
• Platitude – Trite, prosaic, or cliché truism
• Redundancy (linguistics) – Information that is expressed more than once
• Tautophrase – Repetition of an idea in the same words