What is the difference between a language and a dialect?
There is no purely linguistic answer: mutual intelligibility is the usual criterion but it fails in both directions, and in practice the distinction is political — the often-quoted line is that a language is a dialect with an army and a navy.
The obvious test, and why it breaks
Mutual intelligibility seems like the right criterion: if two speakers understand each other, one language. It fails immediately in both directions. Danish, Swedish and Norwegian speakers largely understand each other and are called three languages. Speakers of some Chinese varieties cannot understand each other at all and are called dialects of one.
It is not even symmetric
Intelligibility often runs one way. Speakers of a smaller variety usually understand the prestige one better than the reverse, because they have been exposed to it through media and schooling. A test whose result depends on which speaker you ask is not measuring a property of the languages.
Dialect continua
Across much of Europe, neighbouring villages historically understood each other while the ends of the chain did not. There is no point along the continuum where one language stops and another starts, so any boundary drawn on it is a decision rather than a discovery.
The political answer
The quip attributed to Max Weinreich — a language is a dialect with an army and a navy — is not cynicism. Standardisation, official status, a writing system and a state are what turn a variety into a language in practice, and the same variety can change category when the politics change, as Serbo-Croatian did.
Why it still matters
The label decides whether a variety gets taught, broadcast, subtitled and recorded, which decides whether it survives. Calling something a dialect is frequently the first step in letting it disappear.
Why the count of languages keeps changing
Published totals move by hundreds between editions of the same reference work, and almost none of that is languages appearing or disappearing. It is the boundary being redrawn: a cluster split into three, or three merged into one, usually following better fieldwork or a change in how much weight is given to speaker identity. A number that depends this heavily on a judgement is one to quote with the judgement attached.
Sources
Ethnologue — problem of language identification; Chambers & Trudgill, Dialectology (Cambridge). Every claim above is drawn from these; where a claim is contested or unsettled the article says so rather than picking a side.
How this article was made
Written by a person. Reviewed by Editorial review, Leumas on 2026-09-02. 371 words.
Questions
What is the difference between a language and a dialect?
There is no purely linguistic answer: mutual intelligibility is the usual criterion but it fails in both directions, and in practice the distinction is political — the often-quoted line is that a language is a dialect with an army and a navy.
How do I know this is right?
The sources are listed on the page and a person reviewed it on 2026-09-02. Where a question is genuinely open, the article says so instead of resolving it.