Blocks by User Role for the new WordPress Block Editor (Gutenberg). Conditionally show or hide content in Blocks based on User Role and other filters.
When you export a language file you must use the JED 1.x JSON format. Make sure you get the WordPress Locale Code correct.
(WordPress 5.0 introduced the wp-i18n JavaScript package that provides the functions needed to add translatable strings as you would in PHP where you use .po and the compiled .mo file).