This setting is available for the built-in content modules. For example, to enable this for the News module:
Content > News > click on Settings in the right column > expand Controls > NewsFrontend > Views > NewsFrontendList > type "true" in the Item language fallback field (When in multilingual mode gets or sets whether items with no translation for the current language will be shown.)
How can I apply such a setting for a custom content type?
Scenario: Contacts on a multilingual site should display in their native language on the corresponding language site and in English everywhere else. Contacts are a custom content type with names, bio, email, phone numbers etc. fields.
Example: Our Managing Director in Japan is of Japanese nationality. His name, bio etc. should appear in Japanese on the Japanese language site. His name, bio etc. should appear in English on the US, French and German websites.
Currently, to achieve this, I would need to add French and English "translations" of the content item which contain the English language version. With 300+ contacts and frequent title/bio updates, this is inefficient.
How can I enable language fallback for selected custom content types?