As early as possible in the translation process there should be a hint to the translator that an article with the same title already existed and was deleted.

A similar message exists in the usual MediaWiki article creation process.

There should be a link to the relevant deletion log and the discussion about the deletion.

This doesn't necessarily mean that the article shouldn't be translated; for example, it's quite possible that the previously deleted article was vandalism, but the topic is otherwise notable.

It may make sense to show this already at the article selector, and it should definitely be shown in the columns interface when the title is the same as a title of a deleted article. Showing it when pressing the Publish button is already quite late.

Suggested by a user at https://www.mediawiki.org/wiki/Topic:T7n9oh6qpf40wwbk