Origins
The adjective 'colloquial' entered English in the mid-eighteenth century, formed from Latin 'colloquium' (conversation, conference) with the English suffix '-al.' The Latin noun derives from the verb 'colloquī' (to speak together, to converse), a compound of 'com-' (together, with) and 'loquī' (to speak), the latter tracing to Proto-Indo-European *tolkʷ- (to speak).
The etymology is transparent: 'colloquial' language is language used when people speak together — conversation, as opposed to oration, lecture, or literary composition. But the word's history reveals something important about how societies think about language: the very existence of a word meaning 'conversational' implies that conversation is regarded as a distinct, and often inferior, register of language. To call a word 'colloquial' is typically to mark it as unsuitable for formal contexts — an act of classification that is also an act of judgment.
In classical Latin, 'colloquium' meant a conversation or conference, with no inherent suggestion of informality. Caesar used 'colloquium' to describe diplomatic meetings with enemy leaders — formal, high-stakes exchanges between powers. The word's neutral meaning in Latin contrasts sharply with its use in modern English, where 'colloquial' almost always implies a lower register. This shift reflects the development of prescriptive grammar and the hierarchical classification of linguistic registers that emerged in the early modern period.
Development
The eighteenth century, when 'colloquial' entered English, was an era of intense linguistic anxiety. Samuel Johnson's 'Dictionary of the English Language' (1755) was partly motivated by a desire to fix and stabilize the language, separating 'correct' usage from 'vulgar' or 'low' alternatives. Johnson routinely marked words as 'low,' 'cant,' or 'colloquial,' establishing a taxonomy of linguistic respectability. The word 'colloquial' became a tool in this project of classification.
Linguists today treat 'colloquial' as a descriptive rather than evaluative term. Colloquial language is not 'bad' language — it is language used in informal contexts, characterized by features such as contractions ('don't' instead of 'do not'), phrasal verbs ('put up with' instead of 'tolerate'), slang, and conversational fillers ('like,' 'you know,' 'basically'). Every fluent speaker of a language commands multiple registers and shifts between them according to context. The same person who writes 'the aforementioned document' in a legal brief says 'that thing I mentioned' over lunch.
The distinction between colloquial and formal language varies across cultures and historical periods. In ancient Rome, the gap between literary Latin (the language of Cicero and Virgil) and spoken Latin (the everyday language of markets and streets) was substantial. The Romance languages — French, Spanish, Italian, Portuguese, Romanian — descended not from literary Latin but from colloquial Latin, the spoken registers that evolved and diversified as the Roman Empire fragmented. In a real sense, every Romance language is a child of colloquial speech.
Latin Roots
The noun 'colloquy' — a formal conversation or dialogue — entered English earlier (sixteenth century) and preserves a more elevated sense. Academic 'colloquia' (the Latin plural) are scholarly discussions or seminars. The word 'colloquium' itself has been borrowed directly into English to name an academic seminar or conference, creating an interesting reversal: 'colloquium' in English sounds more formal than 'colloquial,' even though both derive from the same Latin word for speaking together.
The study of colloquial language has become one of the most important areas of modern linguistics. Sociolinguists like William Labov demonstrated in the 1960s and 1970s that colloquial speech is not random or sloppy but follows its own rigorous grammatical rules. The double negative, for instance — condemned in standard English ('I don't know nothing') — is perfectly systematic in many dialects and in many other languages (French 'ne...pas,' Spanish 'no...nada'). What counts as 'colloquial' is determined not by linguistic structure but by social convention.
The related term 'colloquialism' — a word or expression used in ordinary conversation but not in formal speech or writing — entered English in the early nineteenth century. 'Gonna,' 'wanna,' 'kinda,' and 'gotta' are colloquialisms in English. They are not errors; they are systematic phonological reductions that occur naturally in rapid speech. Writing them down merely makes visible what speakers have always done.
Modern Legacy
'Colloquial' thus occupies a paradoxical position in the English vocabulary: a formal, Latinate word used to describe informal, everyday speech. Its etymology — 'speaking together' — reminds us that the oldest and most fundamental form of language is not the essay or the speech but the conversation: two or more people speaking together, creating meaning in real time.