This behavior has been present since 17w45a.
The bug
The difficulty command uses your language's names for the difficulty when it queries the difficulty or successfully changes it. However, when it fails to change it (because the difficulty was already the provided one), the untranslated ID of the difficulty appears instead.
Steps to reproduce
Set the game language to Spanish.
Set the world difficulty to Peaceful:
difficulty peaceful-> ✔ The command feedback is translated.
Query the world difficulty:
difficulty-> ✔ The command feedback is translated.
Try to set the world difficulty to Peaceful again:
difficulty peaceful-> ❌ The command feedback uses the untranslated word "peaceful".
Observed behavior
The error message will use the internal name.
Expected behavior
It would use the localized name, as the success and query messages do.
Linked issues
Attachments
Comments 2
The essence of this error is easier for Russian-speaking people to understand, because the Russian language is also affected by this bug. Therefore, who is Russian (not English-speaking!) here are the steps to reproduce this bug:
Russian Russian is a language other than Russian, then change it to Russian.
Use it /difficulty peaceful
Use /difficulty
Use /difficulty again.
The error message uses the word «Peaceful», which has not been translated into Russian.
Can confirm