It isn't possible to change language in MacOS version

Hello, I saw that on my iMac 2017 Retina4k with High Sierra and the latest MKVToolnix 24 installed from the website (the unsupported release) it isn't possible to select a language in preferences/GUI/interface language: the field is blank and it remains blank even if selected. It is a problem I saw also in the past versions of the software, is it possible to do something? I'm Italian and I would like to see it in my language for an easier use. Thank you in advance :)