English Slang and Informal Language in the United States

Slang is the part of English that dictionaries chase but rarely catch. It moves faster than formal language, marks group identity more sharply than grammar ever could, and carries social information — who belongs, who doesn't, what's cool right now — that no textbook phrase can replicate. This page covers how American slang and informal language are defined, how they function in speech communities, where they appear most visibly, and how to judge when informal usage is appropriate versus when it creates real misunderstanding.

Definition and scope

The Merriam-Webster Dictionary defines slang as "an informal nonstandard vocabulary composed typically of coinages, arbitrarily changed words, and extravagant, forced, or facetious figures of speech." That's accurate as far as it goes, but the working definition used by linguists is a bit more textured.

Slang sits within the broader category of informal language, which itself spans a spectrum. At one end: contractions, clipped words ("fridge," "gym"), and relaxed grammar in casual conversation. At the other: highly specialized in-group vocabulary that functions almost like a code — recognizable only to those already inside a particular community.

The Linguistic Society of America distinguishes slang from three related categories worth keeping clear:

1. Colloquialisms — informal expressions widely understood across a speech community ("gonna," "kinda"), not tied to a specific subgroup
2. Jargon — technical vocabulary within a professional or specialist group (medical, legal, tech)
3. Argot — secretive in-group language historically associated with criminal or marginalized communities, designed partly to exclude outsiders
4. Dialect features — regional vocabulary and grammar patterns tied to geography (explored in depth at English Dialects in the United States)

Slang overlaps with all four but is defined most precisely by its social function: it signals affiliation, contemporaneity, and sometimes resistance to formal norms.

How it works

Slang spreads and transforms through recognizable mechanisms, even when individual words feel spontaneous. Linguists at the American Dialect Society, which has voted on the "Word of the Year" annually since 1990, track these patterns closely.

The primary mechanisms include:

• Semantic shift — existing words acquire new meanings. "Sick" meaning excellent, "ghost" meaning to abruptly cut off contact, "cap" meaning a lie
• Clipping and blending — "sus" from "suspicious," "situationship" blending "situation" and "relationship"
• Borrowing from subcultural communities — much American slang originates in African American Vernacular English (AAVE), as documented by linguist Geneva Smitherman in Talkin and Testifyin (Wayne State University Press, 1977), before moving into mainstream use — a process sociolinguists call "slang diffusion"
• Digital amplification — social platforms accelerate adoption cycles; terms that once took a decade to spread nationally can saturate common usage in under 12 months

The Oxford English Dictionary added over 700 new words and phrases in its March 2023 quarterly update, with a notable proportion drawn from internet-mediated informal English. That volume reflects how fast the informal lexicon is expanding, not just shifting.

For learners working through informal vocabulary alongside formal rules, the foundational concepts at English Grammar Fundamentals provide useful grounding for understanding why slang often violates — and sometimes reinforces — standard grammatical structure.

Common scenarios

Informal language surfaces predictably in specific contexts, each with its own conventions.

Peer conversation is the native habitat of slang. Among friends and age cohorts, informal vocabulary signals solidarity. Using formal register in casual peer settings can read as stiff or even condescending — linguists call this register mismatch.

Workplace communication occupies a middle zone. Professional environments in the United States increasingly tolerate colloquial language in informal exchanges (Slack messages, hallway conversations), while expecting standard register in written reports, presentations, and client-facing communication. Business Writing in English addresses where that boundary sits in professional contexts.

Media and entertainment is perhaps the highest-visibility environment. Television, music, film, and social content both reflect and actively shape informal usage. The Media and Communication Studies work of the National Communication Association notes that mass media accelerates slang adoption by exposing terms to audiences far outside the originating community.

Non-native speaker contexts deserve specific attention. The American Council on the Teaching of Foreign Languages (ACTFL) proficiency guidelines don't formally assess slang competency, but slang literacy is often what separates an intermediate-level English speaker from one who sounds genuinely fluent. A learner who has mastered grammar but encounters "no cap," "lowkey," or "it's giving" without context is holding a sentence that standard parsing cannot decode.

Decision boundaries

Knowing whether informal language is appropriate in a given situation requires reading three variables: audience, medium, and relationship.

A reliable framework, grounded in register theory as described in the English Language Arts Curriculum standards used by the National Council of Teachers of English (NCTE):

• Formal register — academic writing, legal documents, official correspondence, public speeches. Slang is inappropriate here; even colloquialisms warrant caution.
• Consultative register — professional meetings, interviews, transactions with strangers. Standard informal English is acceptable; slang is generally avoided unless the relationship is already established.
• Casual register — conversation with friends, peers, familiar colleagues. Slang is natural and expected. Avoiding it entirely can feel performative.
• Intimate register — close personal relationships. Highly personalized informal language, including private coinages, is normal.

The contrast between formal and casual registers maps directly onto the broader American English vs British English divide as well — American informal English is notably more permissive in professional settings than British formal conventions, a difference that matters in cross-cultural communication.

The fuller English Language and Culture in the US context shapes which informal expressions are understood nationally versus which remain regional or subcultural — an important distinction for anyone navigating the full range of American English. The English Language Authority homepage provides a structured starting point for exploring formal and informal dimensions of the language together.