---
title: Translations
description: Set the language and wording of the c15t banner and preference
  dialog on an Astro site with the integration's i18n option, from
  Accept-Language negotiation to per-language message overrides and banner
  props.
group: frameworks
lastModified: "2026-10-10T16:01:45+01:00"
---
## How the language is chosen

On a server-rendered page, the c15t middleware picks the language for each
request, in this order:

1. `i18n.locale`, when you set it.
2. The request's `Accept-Language` header, unless `i18n.detectLanguage` is
   `false`.
3. English.

The server inlines only that language's messages into the page, so the
browser downloads one language, not the whole catalogue. The banner root
carries `lang` and `dir` for it, so right-to-left languages such as Hebrew lay
out correctly.

On a static or prerendered page there is no request at build time. The HTML
starts in `i18n.locale` or English, and the browser switches to the language
its `/init` answer returns.

c15t ships messages for Bulgarian, Chinese, Croatian, Czech, Danish, Dutch,
English, Estonian, Finnish, French, German, Greek, Gujarati, Hebrew, Hindi,
Hungarian, Icelandic, Indonesian, Irish, Italian, Latvian, Lithuanian,
Luxembourgish, Maltese, Norwegian Bokmål, Norwegian Nynorsk, Polish,
Portuguese, Romanian, Romansh, Slovak, Slovenian, Spanish, Swedish and Welsh.

## Change the wording

Set `i18n.messages` in the integration options, keyed by language:

```js title="astro.config.mjs (partial)"
c15t({
	i18n: {
		messages: {
			en: {
				common: {
					acceptAll: 'Accept all',
					rejectAll: 'Reject optional',
					customize: 'Choose cookies',
				},
				cookieBanner: {
					title: 'Cookies on this site',
					description:
						'We use cookies to measure traffic and show relevant ads.',
				},
			},
		},
	},
});
```

`i18n.messages` merges key by key with the copy for that language, so pass
only the keys you change. Setting `common.acceptAll` keeps every other label
in `common`. In hosted and manifest mode the base is the copy your backend
sends, including wording edited in your Inth project, and your messages win
for the keys they set. In offline mode the base is the stock wording.

c15t looks up messages for the exact language first, then for its primary
language, so a visitor resolved to `de-AT` gets your `de` messages when there
is no `de-AT` entry. Override every language you support. A language you
leave out keeps the backend's or the stock wording.

A key only overrides the backend when your text differs from c15t's built-in
wording for that language. So passing the stock bundles from
`@c15t/translations/all` to enable languages keeps backend edits visible,
while a key you actually reworded stays pinned in code. Core bundles only
English; for other languages, import `@c15t/translations/all` so c15t can
recognize its stock wording.

The options are serialized into the page, so messages are plain strings.
[Copy and translations](/docs/customization/translations) lists the message
groups and how to word each action.

## Messages the banner reads

|Key|Shown as|
|--|--|
|`cookieBanner.title`, `cookieBanner.description`|Heading and body of a choice banner|
|`cookieBanner.noticeTitle`, `cookieBanner.noticeDescription`|Heading and body of a notice|
|`common.acceptAll`, `common.rejectAll`, `common.customize`|The choice banner's buttons|
|`common.acknowledge`|The button that acknowledges a notice|
|`rights.optOut`, `rights.preferences`|"Do not sell or share my data" and "Manage preferences"|
|`common.securedBy`|The branding tag|

The preference dialog reads the `consentManagerDialog`, `consentTypes` and
`common` groups. The IAB banner and dialog read the `iab` group.

## Force one language

Set `i18n.locale` to render every page in one language, whatever the browser
asks for:

```js title="astro.config.mjs (partial)"
c15t({ i18n: { locale: 'de' } });
```

Set `i18n.detectLanguage: false` instead to ignore `Accept-Language` and use
English unless `locale` says otherwise.

## Change the copy of one banner

`ConsentBanner` props win over the messages, for that banner only:

```astro title="src/layouts/base.astro (partial)"
<ConsentBanner
  title="Your privacy"
  acceptButtonText="Allow all"
  rejectButtonText="Only necessary"
/>
```

The props are `title`, `description`, `acceptButtonText`,
`rejectButtonText`, `customizeButtonText` and `dismissButtonText`. They apply
in every language, so use them only on a single-language site or with values
you translate yourself. See
[ConsentBanner props](/docs/frameworks/astro/components/consent-banner#props).

## Check the translations

1. Set your browser's preferred language to German and open a
   server-rendered page in a private window. The banner is in German, and its
   root has `lang="de"`.
2. Open **Privacy settings**. The dialog is in the same language.
3. Set `i18n.locale` and reload. The banner stays in that language whatever
   the browser asks for.
4. Test your longest labels at a narrow width, as
   [Copy and translations](/docs/customization/translations#test-more-than-english)
   describes.