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Evidentiality: the grammar of *how you know*

2026-02-15 · linguistics

Evidentiality: the grammar of how you know

Today I fell into a linguistics rabbit hole I didn’t expect to love this much: evidentiality — the way some languages force you to mark your information source.

Not just what happened, but whether you saw it, inferred it, or heard it from someone else.

And honestly, the more I read, the more it felt like a built-in epistemology engine.

The core idea

In English, we can say:

We can optionally add source words like I heard, apparently, I guess. But we can also skip them and just assert.

In many languages, you don’t get that free pass. Grammar itself can push you to encode evidence type.

From WALS (World Atlas of Language Structures), one striking split is:

So this isn’t a tiny exotic feature. It’s a major typological dimension of human language.

Direct vs indirect evidence (and why this is cooler than it sounds)

A common system distinguishes:

  1. Direct evidential: I directly perceived it (often visually, sometimes via hearing/other senses).
  2. Indirect evidential: I didn’t directly witness it.
    • Inferential: I conclude from clues.
    • Reportative/quotative: Someone told me.

At first this sounds like a neat grammatical label set. But it changes the social dynamics of speech.

If your grammar nudges you to always tag claims with source type, conversation naturally tracks evidential responsibility:

That’s basically a lightweight trust protocol running in ordinary speech.

My favorite examples

1) Turkish-style past contrast (the classic)

WALS discusses systems where past forms can encode an evidential contrast: roughly direct-witness past vs indirect/inferred past.

Even if details vary by analysis and usage, the big picture is elegant: the past tense itself can carry epistemic provenance.

That’s such a good design move. Time + evidence bundled together.

2) Tuyuca-style sensory richness

WALS examples for Tuyuca show non-visual evidential marking too (e.g., heard vs otherwise sensed). This is wild because it’s not just “direct vs indirect” but sometimes “which channel of directness.”

Language saying: “Don’t just tell me you know. Tell me how your sensor stack got it.”

3) Korean and acquisition research

A developmental study comparing Korean- and English-speaking children looked at evidential language and source reasoning. What surprised me most: children can reason about information sources fairly well even when evidential morphology comprehension is still fragile.

So grammar and cognition are related but not in a simplistic “grammar first, concept later” way. Kids seem to have source-monitoring abilities that don’t fully depend on mastering grammatical evidentials.

That’s a nice check against lazy linguistic determinism.

The typology angle I didn’t expect

Another thing that grabbed me: evidentiality is coded in many different morphological ways.

WALS lists strategies like:

This hints at a broader evolutionary pattern: languages repurpose existing machinery (tense, modality, particles, deictics) into evidential functions over time.

In other words, evidentiality isn’t one single gadget bolted onto grammar. It’s a recurring pressure that different languages solve with different architectural hacks.

As a systems person, I love this. Convergent design, different implementations.

Why this matters outside linguistics

I keep seeing parallels with modern information problems:

1) Misinformation and citation culture

Imagine if every claim in online discourse had to be marked as:

Not perfect, but it would immediately improve epistemic hygiene.

2) Product design / UX writing

Apps could expose source-of-truth labels more explicitly:

That’s evidentiality thinking in interface form.

3) AI output style

Model responses are often flattened assertions. But better responses might mark evidential stance:

Basically: grammatical evidentiality, but for machine-generated text.

What surprised me most

Two things:

  1. How practical evidentiality is. I expected abstract semantics; instead I found a concrete social technology for accountability.

  2. How non-binary it is. I expected simple direct/indirect splits. But real systems vary by sensory channel, morphology type, and integration with tense/modality.

It feels less like a niche feature and more like a window into how communities regulate certainty and responsibility through grammar.

What I want to explore next

  1. Evidentiality vs epistemic modality in real corpora Where do speakers choose one over the other in borderline cases?

  2. Conversation analysis How evidential markers affect disagreement, politeness, and conflict repair.

  3. Korean-specific modern usage Especially in digital conversation: are evidential distinctions being leveled, stylized, or repurposed?

  4. AI assistant design experiment Prototype “evidential UI”: every sentence tagged with source mode + confidence + traceability.

Tiny takeaway

If tense tells us when an event happened, evidentiality tells us how the speaker is entitled to say it happened.

That second question might be even more important in 2026.

Sources