Why Words Change Meaning: The Science of Semantic Shift and How Language Evolves Under Our Feet
The word "nice" once meant "foolish" or "ignorant." It comes from the Latin nescius, meaning "not knowing." Over the course of several centuries, it passed through meanings including "timid," "fussy," "precise," "delicate," "pleasant," and finally settled into its current sense of "kind" or "agreeable." At no point did anyone decide to change its meaning. No committee voted to upgrade "nice" from insult to compliment. The change happened gradually, through millions of individual acts of usage in which speakers stretched, adapted, and shifted the word's meaning to serve their communicative needs.
This transformation--from "ignorant" to "kind"--is not exceptional. It is normal. Every word in every language is either currently changing meaning or has changed meaning in the past. The English you speak today is full of words whose current meanings would baffle the speakers who used them a few centuries ago, and the English your grandchildren will speak will contain meanings that would baffle you.
Semantic change--the shift in word meanings over time--is one of the most fascinating and most misunderstood aspects of language. It is not corruption. It is not decay. It is not a sign that people are getting stupider or lazier. It is the natural, inevitable, and necessary process by which language adapts to the changing needs, experiences, and social realities of its speakers.
Why Do Word Meanings Change?
Semantic change is driven by several interacting forces, each pulling word meanings in different directions.
1. Metaphorical Extension
The most creative driver of meaning change is metaphor--the application of a word from one domain to another based on perceived similarity.
- "Grasp" originally meant to seize physically; it now also means to understand intellectually (seizing an idea as one seizes an object)
- "Bright" originally described light; it now also describes intelligence (smart people "illuminate" understanding)
- "Navigate" originally described steering a ship; it now describes moving through any complex system (navigating a website, navigating a relationship)
- "Cloud" originally described a visible mass of water vapor; it now describes remote data storage (the metaphor of information floating overhead, accessible from anywhere)
Metaphorical extension is the primary mechanism through which languages acquire vocabulary for abstract concepts. Most abstract words in any language can be traced back to concrete physical origins:
- "Understand" likely derives from "standing under" or "standing among" (physically being in the midst of something)
- "Comprehend" comes from Latin comprehendere, meaning to grasp or seize physically
- "Consider" comes from Latin considerare, which may originally have meant to observe the stars (sidera)
- "Translate" comes from Latin translatus, meaning to carry across
2. Social and Cultural Change
When society changes, the meanings of words change to keep pace:
- "Computer" once meant a person who computes (a human mathematician). The invention of electronic computing machines transferred the word to the machine, eventually eliminating the human reference entirely.
- "Gay" meant "lighthearted" or "carefree" through most of its English history. Its association with homosexuality emerged in the mid-twentieth century and has now become the primary meaning, largely displacing the older sense.
- "Awful" originally meant "full of awe"--inspiring reverence and wonder. As the word was increasingly used for negative sources of awe (terrible sights, frightening events), the meaning shifted from "awe-inspiring" to simply "terrible."
- "Broadcast" originally meant to scatter seeds widely. Radio technology adopted the metaphor of "scattering" information widely, and the agricultural sense has been almost entirely replaced.
3. Technological Innovation
New technologies create pressure for new vocabulary, and languages typically respond by extending existing words rather than inventing entirely new ones:
- "Mouse" (computing device): Extended from the rodent based on physical resemblance
- "Web" (the internet): Extended from spider's web based on the network structure
- "Stream" (media delivery): Extended from flowing water based on continuous flow
- "Bug" (software error): Extended from insect, possibly from an actual moth found in an early computer
- "Viral" (content spread): Extended from biological virus based on rapid, uncontrolled replication
This technological extension of existing words is not unique to the digital age. The words "train," "car," "engine," "drive," "channel," and "record" all acquired technological meanings during earlier periods of innovation.
4. Generational Differentiation
Each generation develops its own vocabulary partly to signal generational identity and distinguish itself from older generations:
- "Groovy" (1960s), "rad" (1980s), "phat" (1990s), "lit" (2010s), "bussin" (2020s)--each generation's slang serves the same social function (positive evaluation) but uses different words to mark generational belonging
- Existing words acquire new generational meanings: "sick" (excellent), "fire" (impressive), "slay" (perform excellently), "mid" (mediocre)
This generational meaning-shift is one of the most visible and most contested forms of semantic change. Older speakers who encounter familiar words used with unfamiliar meanings often experience the change as confusion, irritation, or evidence of linguistic decline.
5. Euphemism Treadmill
Words that refer to taboo, sensitive, or uncomfortable topics undergo a characteristic pattern of meaning deterioration:
- A new, neutral or positive term is introduced for a stigmatized concept (e.g., "differently abled")
- Through association with the stigmatized concept, the term acquires negative connotations
- A new term is introduced to replace the now-tainted one
- The cycle repeats
This pattern is visible in the history of terms for intellectual disability ("idiot" > "moron" > "retarded" > "mentally handicapped" > "intellectually disabled"), for elderly people ("old" > "senior" > "elderly" > "older adult"), and for many other socially sensitive concepts.
The linguist Steven Pinker called this the "euphemism treadmill": no matter how carefully a neutral term is chosen, association with a stigmatized concept eventually contaminates it, requiring replacement. The semantic change is driven not by anything wrong with the word itself but by the social attitudes attached to what it refers to.
6. Natural Drift
Some semantic change occurs without any obvious social or cultural driver--words simply drift in meaning through accumulated minor shifts in usage:
- "Meat" once meant food in general (as in "meat and drink"). It gradually narrowed to mean specifically animal flesh.
- "Deer" once meant any animal (German Tier still has this broader meaning). It narrowed to mean a specific type of animal.
- "Starve" once meant to die from any cause (German sterben still means "to die"). It narrowed to mean specifically dying from hunger.
Types of Semantic Change
Linguists have identified several recurring patterns of semantic change.
Broadening (Generalization)
A word's meaning expands from a specific sense to a more general one:
- "Dog" once referred to a specific breed; now means any canine
- "Bird" once meant a young bird specifically; now means any bird
- "Salary" comes from Latin salarium (salt money--money given to soldiers to buy salt); now means any regular payment for work
- "Holiday" comes from "holy day" (a religious observance); now means any day of rest or vacation
Narrowing (Specialization)
A word's meaning contracts from a general sense to a more specific one:
- "Meat": General food > animal flesh specifically
- "Deer": Any animal > a specific animal family
- "Wife": Any woman > specifically a married woman
- "Hound": Any dog > a specific type of dog
- "Liquor": Any liquid (liquor in Latin) > specifically alcoholic drink
Amelioration (Improvement)
A word's meaning shifts from negative or neutral to more positive:
- "Nice": Ignorant/foolish > pleasant/kind
- "Knight": Boy/servant > honorable warrior/nobleman
- "Fond": Foolish > affectionate
- "Pretty": Cunning/tricky > attractive
- "Terrific": Terrifying > excellent
Pejoration (Deterioration)
A word's meaning shifts from positive or neutral to more negative:
- "Silly": Blessed/happy > innocent/harmless > foolish
- "Villain": Farm worker (Latin villanus) > wicked person
- "Notorious": Simply well-known > well-known for bad reasons
- "Awful": Full of awe/inspiring > terrible
- "Egregious": Outstanding/remarkable > outstandingly bad
| Change Type | Direction | Example | Old Meaning | New Meaning |
|---|---|---|---|---|
| Broadening | Specific > General | "Holiday" | Religious holy day | Any day off |
| Narrowing | General > Specific | "Meat" | Any food | Animal flesh |
| Amelioration | Negative > Positive | "Nice" | Ignorant | Pleasant |
| Pejoration | Positive > Negative | "Villain" | Farm worker | Evil person |
| Metaphor | Concrete > Abstract | "Grasp" | Seize physically | Understand |
Metonymy
A word's meaning shifts to something associated with it:
- "Crown": A physical object > the institution of monarchy
- "The press": A printing press > journalism as an institution
- "Hollywood": A geographic location > the film industry
- "Pen": A writing instrument > written expression ("the pen is mightier than the sword")
- "Tongue": A body part > a language ("mother tongue")
How Fast Do Word Meanings Change?
The speed of semantic change varies enormously depending on the word, the social context, and the forces driving the change.
Rapid Change (Months to Years)
Slang changes meaning rapidly because its social function depends on novelty. When a slang term becomes mainstream, it loses its value as an in-group marker and is replaced:
- "Sick" went from exclusively negative to potentially positive within a decade
- "Literally" expanded from its literal meaning to an intensifier ("I literally died") within a generation
- Social media creates especially rapid semantic change: "ratio'd," "based," "cope," "slay" all acquired their internet-specific meanings within a few years
Moderate Change (Decades to Centuries)
Most standard vocabulary changes meaning over decades to centuries:
- "Awesome" took several decades to shift from "inspiring awe" to "really good"
- "Manufacture" took centuries to shift from "made by hand" (Latin manu facere) to "made by machine"
Slow Change (Centuries to Millennia)
Core vocabulary--basic words for body parts, family relationships, small numbers, and fundamental natural phenomena--changes meaning very slowly. Words for "mother," "water," "sun," "eye," and small numbers have remained relatively stable across millennia in many language families.
Acceleration Factors
Several factors are accelerating semantic change in the modern era:
- Social media enables new usages to spread to millions of speakers in days rather than years
- Global communication exposes speakers to more varied usages from more diverse communities
- Reduced prescriptive authority (fewer people consulting dictionaries or deferring to language authorities) allows innovation to spread more freely
- Rapid cultural change creates constant demand for new meanings to describe new experiences
Can Semantic Change Be Prevented?
No. This finding is one of the most robust in linguistics.
Why Prevention Fails
- Language exists in speakers' minds, not in dictionaries: Dictionaries record usage; they do not control it. When speakers change how they use a word, the dictionary eventually follows.
- Semantic change is decentralized: No individual or institution controls how millions of speakers use words. Change emerges from the aggregate of countless individual usage decisions.
- Change serves social functions: Speakers change word meanings because doing so serves their communicative, social, and identity needs. Preventing change would require preventing speakers from adapting language to their needs.
- Prescription creates variation, not uniformity: When authorities declare a usage "incorrect," the result is typically two coexisting meanings (the "correct" one and the "incorrect" one that most people actually use) rather than the elimination of the new meaning.
Historical Attempts and Their Outcomes
- The Academie Francaise has been attempting to prevent semantic change in French since 1635. French has continued to change.
- English dictionaries have been declaring usages "incorrect" since Samuel Johnson's 1755 dictionary. Those usages have often become standard.
- Every generation has included commentators who believed that current semantic changes represented unique degradation. Every such commentator has been proven wrong by subsequent generations who communicated just as effectively with the changed meanings.
Why Do Older Generations Resist New Meanings?
The resistance of older speakers to semantic change is one of the most predictable social dynamics in language.
Cognitive Investment
Speakers have invested decades in learning word meanings, and encountering familiar words with unfamiliar meanings creates cognitive disruption. "Literally" meaning "figuratively" is not just linguistically irritating to those who learned the older meaning--it is cognitively disorienting, because the word no longer does what the speaker expects it to do.
Identity and Belonging
Language is tied to identity. The way you speak marks you as belonging to a particular generation, region, class, and social group. When younger speakers change the language, older speakers may experience this as an erosion of the linguistic world they inhabit--not just a change in vocabulary but a change in the culture that the vocabulary represents.
Perceived Decline
Many people hold an implicit belief that language should be stable and that change represents decline. This belief is understandable (stability feels safe; change feels threatening) but linguistically unfounded. No generation has ever communicated less effectively than the one before it, despite the constant changes that each generation introduces.
The Generation Gap Cycle
The pattern is remarkably consistent across generations:
- Young people develop new usages
- Older people notice and object
- The new usages spread despite objections
- The young people grow old and begin objecting to the next generation's innovations
- The cycle repeats
Shakespeare's contemporaries objected to his linguistic innovations. Victorian grammarians objected to usages that are now standard. Twentieth-century prescriptivists objected to "contact" as a verb, "hopefully" as a sentence adverb, and "they" as a singular pronoun--all of which are now unremarkable in standard English.
Does Semantic Change Harm Communication?
In the short term, semantic change can create temporary confusion between groups that use different meanings:
- A teenager saying "That's sick!" (meaning excellent) to a grandparent who hears "sick" as negative
- A professional using "literally" for emphasis while a colleague interprets it as factual assertion
- A social media user describing something as "mid" while an older interlocutor has no reference for the term
This confusion is real but temporary and self-correcting. As new meanings spread through the language, they become the standard, and the confusion dissipates. The period of confusion is the transitional phase during which old and new meanings coexist, and it is a natural (if sometimes frustrating) part of the process by which language adapts.
The Net Effect
Over the long term, semantic change does not harm communication. It maintains communication by ensuring that language remains adapted to the communicative needs of its current speakers. A language that could not change meanings would be a language that could not describe new technologies, new social arrangements, new experiences, or new ideas. It would be a language that was functionally dead--preserved in its form but incapable of serving the needs of living speakers.
Every language in active use is simultaneously ancient in its deepest structures and brand new in its latest innovations. This combination of stability and change is not a defect. It is the mechanism by which human language has remained humanity's most powerful and adaptable tool for over a hundred thousand years--changing constantly so that it can continue to do what it has always done: give people the words they need to describe the world they live in.
References and Further Reading
Traugott, E.C. & Dasher, R.B. (2001). Regularity in Semantic Change. Cambridge University Press. https://doi.org/10.1017/CBO9780511486500
Blank, A. & Koch, P., eds. (1999). Historical Semantics and Cognition. Mouton de Gruyter. https://doi.org/10.1515/9783110804195
Geeraerts, D. (2010). Theories of Lexical Semantics. Oxford University Press. https://en.wikipedia.org/wiki/Dirk_Geeraerts
Aitchison, J. (2013). Language Change: Progress or Decay? 4th ed. Cambridge University Press. https://en.wikipedia.org/wiki/Jean_Aitchison
Campbell, L. (2013). Historical Linguistics: An Introduction. 3rd ed. MIT Press. https://en.wikipedia.org/wiki/Historical_linguistics
Pinker, S. (1994). The Language Instinct: How the Mind Creates Language. William Morrow. https://en.wikipedia.org/wiki/The_Language_Instinct
Lakoff, G. & Johnson, M. (1980). Metaphors We Live By. University of Chicago Press. https://en.wikipedia.org/wiki/Metaphors_We_Live_By
Sweetser, E. (1990). From Etymology to Pragmatics: Metaphorical and Cultural Aspects of Semantic Structure. Cambridge University Press. https://doi.org/10.1017/CBO9780511620904
Ullmann, S. (1962). Semantics: An Introduction to the Science of Meaning. Blackwell. https://en.wikipedia.org/wiki/Stephen_Ullmann
Breal, M. (1900). Semantics: Studies in the Science of Meaning. Trans. Mrs. Henry Cust. Henry Holt. https://en.wikipedia.org/wiki/Michel_Br%C3%A9al
Hopper, P.J. & Traugott, E.C. (2003). Grammaticalization. 2nd ed. Cambridge University Press. https://en.wikipedia.org/wiki/Grammaticalization
McWhorter, J. (2001). The Power of Babel: A Natural History of Language. Times Books. https://en.wikipedia.org/wiki/John_McWhorter
Crystal, D. (2011). Internet Linguistics: A Student Guide. Routledge. https://en.wikipedia.org/wiki/David_Crystal