---
title: "I18n & Localization"
description: "How Nuxt SEO Utils handles language and locale configuration."
canonical_url: "https://nuxtseo.com/docs/seo-utils/guides/i18n"
last_updated: "2026-05-22T16:40:33.909Z"
---
## Introduction
Nuxt SEO Utils automatically sets the `` attribute and locale-based meta tags for your site.
## How is Locale Used?
Nuxt SEO Utils will automatically set:
- `` - Current locale based on your configuration
- `og:locale` - OpenGraph locale (e.g., `en_US`, `ja_JP`)
- Schema.org `inLanguage` - For WebSite, WebPage, and other structured data (when using [Nuxt Schema.org](/docs/schema-org/getting-started/introduction))
- `useBreadcrumbItems()` - Automatically handles locale-prefixed routes and translates labels via i18n keys (`breadcrumb.items.{routeName}.label`)
- Fallback page titles - Automatically resolves titles from i18n translations using `pages.{routeName}.title` keys
`og:locale` requires a locale format with underscore (e.g., `en_US`). If your locale is just `"en"`, the module won't set `og:locale` automatically. When `@nuxtjs/i18n` is configured with SEO head enabled, it handles `og:locale` directly and takes priority.
## How Locale is Determined
When `automaticDefaults` is enabled (default), the module sets the `lang` attribute using this priority:
1. **@nuxtjs/i18n or nuxt-i18n-micro module** - Automatically detected and integrated
2. **Site Config currentLocale** - Dynamic locale from `useSiteConfig()`
3. **Site Config defaultLocale** - Static default from `nuxt.config.ts`
4. **Fallback** - Defaults to `"en"`
The locale is set with **low priority**, allowing you to override it manually if needed.
## Setting up Nuxt SEO Utils for I18n
If you're building a multilingual site, install `@nuxtjs/i18n`.
For single language sites without `@nuxtjs/i18n`, set the locale via Site Config:
```ts [nuxt.config.ts]twoslash
export default defineNuxtConfig({
site: {
defaultLocale: 'ja-JP'
}
})
```
Set your locale as specific as possible using BCP 47 format (hyphen-separated). Instead of `en`, use `en-US`, `en-AU`, or whatever is appropriate for your site. The module automatically converts this to underscore format (`en_US`) for `og:locale`.
## Dynamic Locale Changes
If you need to change the locale dynamically without using the I18n module, use `updateSiteConfig()`:
```vue
```
## Manual Control
To manually control all locale settings, disable automatic defaults:
```ts [nuxt.config.ts]twoslash
export default defineNuxtConfig({
seo: {
automaticDefaults: false
}
})
```
Then set everything manually:
```ts [app.vue]
useHead({
htmlAttrs: { lang: 'ja-JP' }
})
useSeoMeta({
ogLocale: 'ja_JP'
})
```