# `jsx-a11y/html-has-lang` - **Category:** Accessibility - **Severity:** warn - **Source:** oxlint-builtin:jsx-a11y - **Framework:** global - **Enabled when:** always (unless customRulesOnly=true) - **Documentation:** ## Validation prompt Use this to decide whether a fired diagnostic is real or a false positive. Fires on a JSX element without a lang prop, or with lang set to an empty string. The rule only inspects the literal tag in the current file. False positive: in Next.js App Router, lang is set on in the root layout — a deeper file rendering its own usually indicates a different structural problem, not a missed attribute. ## Fix prompt Use this once validation confirms the diagnostic is real. Add a BCP 47 language code: for English, for regional variants, or driven from i18n state. Screen readers use lang to switch pronunciation rules and dictionaries; without it, they fall back to the user's OS language and mispronounce content. See https://oxc.rs/docs/guide/usage/linter/rules/jsx_a11y/html-has-lang