Dynamics 365 Business Central is multi-language enabled, which means that you can display the user interface in different languages and you need to support that feature when developing extensions.
With classic NAV development in C/SIDE, you manage the multi-language captions by using the CaptionML property: https://docs.microsoft.com/en-us/dynamics-nav/captionml-property.
As you've probably seen, in our previous extension, we haven't managed the translation of the captions that we have in our code. You can't find lines with the CaptionML set, for example the following:
field(2; Description; Text[50]) { DataClassification = CustomerContent; CaptionML = ENU = 'Description', ITA = 'Descrizione'; }
But instead, ...