# Force a locale in Rails I18n from the params

If you want to change the local used for internationalization a single time from the params of the URL you need to use the `with_locale` method.

```ruby
message = I18n.with_local params[:locale] do
  I18n.t("key.to.message")
end
```

Now your `message` will be in the locale received from the params of the URL, if it was not defined it would fallback to the default locale configured in your application.