If you listen to the audio files of the game, then in all languages (except French) the name of the skull sounds like [Mort]*
In official translations of texts in all languages, the name of the skull is spelled the same - "Morte". As Google shows me, this is correct only for English, Czech and French, where the letter "e" at the end of a word is not pronounceable, and the word reads like [Mort]. However, in German and Polish, in the word "Morte" the letter "e" is readable and the word is pronounced like [Morte]. Considering that audio dialogs are quite rare and the name of the skull is perceived precisely from what is written, we can see that Polish and German players are forced to read it incorrectly. The skull is [Mort], not [Morte]. Which incidentally was confirmed by the character creator Chris Avellone when I asked him this question on Facebook.
A separate question on the French language. We hear [Morte] in the audio files, but Google showed me that the word "Morte" in French sounds like [Mort]. Does that means it is spelled correctly, but there is an error in the dubbing? Or is it some feature of the French language where the [Mort] sound cannot exist?
This problem is also present in unofficial Russian translations, where instead of «Морт»([Mort]), it is written «Мортэ»([Morte])
Doesn't it seem to the respected community that we are facing some kind of confusion and that the name of one of the main characters of the game should not be distorted in this way?
*here and below in square brackets is the sound of the word