Step1: Rename existing category with the following format
From Knowledge Base admin panel edit category name to the following multi-lingual format
@{appname.section.name|Display Name}
for knowledge base we suggest to put
@{kbase.cat.name|DisplayName}
here is an example for a category name "Office"
Step 2 Adding Localisation Key
Navigate to Admin > System > Localisation
Under Your changes click on Core Apps...
Right click to add new phrase
Enter the translation, here is an example
Click Save button at the bottom of the list page and close the window once you're done.
Step 3 Test!
Navigate back to the Knowledge Base application to check the category name and try changing your settings to different language.