Can Drush display translated messages to users?

I'm working on a module which extended DrushCommands to create custom Drush commands. The maintainer wants those custom commands to display translatable custom messages (warnings, erros) upon usage.

(How) Can It be achieved?

After some research i was able to achieve this using Drush's logger method together with t() method.

$this->logger()->error($this->t('message with @arg', ['@arg' => $arg]));

Also defined a const ERRORCODE = 0 and returned self::ERRORCODE; to stop logger from sending the complete stack trace on the screen and guarantee that the correct error code is being returned when an error is thrown.

I thank you all for your help and i hope this can be useful for someone in the future :D

In the past there was the system that dt() would simply print translated strings that happened to have a translation in Drupal, if you've set a default_language in a drushrc.php file.

Modern Drush now does the same simply following your site's default language. But there's no way of overriding this from drush.yml anymore. Although this shouldn't be too difficult to implement.

Quoting Drush's core maintainer Moshe Weitzman I asked about that on drupal.slack.com in the #drush channel:

There are no plans to add translation to drush output. Symfony Console apps have a standard but you have to separate your strings from your code and thats poor DX IMO.

I guess the only possible road to take now would be to create an issue to re-implement the possibility to override the language_default from drush.yml and provide that in a nice merge request.

Still you'd need to find a way to get the Drush core strings into the database somehow. Maybe from a nice new contrib module that parses all dt() strings and adds them to the database, so that you'd find them later on the interface translation page.