Set Up Language Mapping in Your CMS Connection
Language Mapping allows you to have copies of your entire site in other languages. It doesn’t matter how your languages are named in your CMS. Use language mapping to configure a mapping to Salesforce languages.
In AEM, language names are in the directory
The directory for French is:
fr is the CMS Language, which you can map to the Salesforce language
Let’s say you mapped all the languages from your CMS to Salesforce languages. That doesn’t necessarily mean all those languages are enabled in your site. To check, go to Experience Builder, and click Settings | Languages. If any are missing, add them.
Your site can have some languages enabled that don’t exist in your CMS. You can also map these languages to define which language the CMS content displays in.