Language Field Guide
The Language field provides a drop down list of the installed languages for the front-end or back-end. The value saved is the language tag. For example, for English (United Kingdom) this will be en-GB.
Field Settings
Header: Placeholder text for the first item in the drop down (value is empty). For example, "- Select Language -".
Form Layout: Choose the layout that will be used to render the field.
Client: Choose 'Site' if you want to list the front-end languages or 'Administrator' if you want to list the back-end languages.