in nopcommerce the default fallback behavior of asp.net (exists at least since framework version 2.0) is not existent.
With no resource entry in the common language nopcommerce shows the keys instead of the default values.
Why don't you use the ASP.Net defaults for resource handling, which is descriped at following link?
We had this feature in our own shop solution, based on sql-Server database, since 20 years. Perhaps we can help to make nopCommerce more comfortable?
https://learn.microsoft.com/en-us/aspnet/core/fundamentals/localization/provide-resources?view=aspnetcore-8.0
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Culture fallback behavior
When searching for a resource, localization engages in "culture fallback". Starting from the requested culture, if not found, it reverts to the parent culture of that culture. As an aside, the CultureInfo.Parent property represents the parent culture. This usually (but not always) means removing the national signifier from the language-and-culture code. For example, the dialect of Spanish spoken in Mexico is "es-MX". It has the parent "es"—Spanish non-specific to any country.
Imagine your site receives a request for a "Welcome" resource using culture "fr-CA". The localization system looks for the following resources, in order, and selects the first match:
Welcome.fr-CA.resx
Welcome.fr.resx
Welcome.resx (if the NeutralResourcesLanguage is "fr-CA")
As an example, if you remove the ".fr" culture designator and you have the culture set to French, the default resource file is read and strings are localized. The Resource manager designates a default or fallback resource for when nothing meets your requested culture. If you want to just return the key when missing a resource for the requested culture you must not have a default resource file.