Even with the developer included MTL, I found the text hard to actually follow in English. Thus, I decided to try and edit a collage of MTL sources to try and make something more palatable. I used DeepL, Google, Bing, Baidu, Yandex, etc. Please keep in mind I have zero understanding of the written Japanese language, so translation accuracy is most likely dookie. Even still, it should be much easier to follow than the straight raw MTL.
Credit goes to Hoggy at ULMF for pointing me to the files that could be edited with his initial (now removed due to the dev's MTL) UI MTL translation on page 2 of this game's ULMF thread. Also for his installation instructions that I'm borrowing as I've just edited the same files he did.
I've translated and edited all .csv files and all other text files I could see to edit in the StreamingAssets folder. I have not playtested any of the translation past the tutorial, so there may still be some MTL jankiness in places. Also, I have not yet really played much as I wanted to finish this first so some terminology may not fit 100%.
I started doing this for you own personal use, but figured other people may be interested so decided to share what I ended up with here. I've checked everything up to v1.20 and everything that can be translated should be. I know the calendar is still in Japanese, but unfortunately I can't seem to find where it's pulling that text or picture from. If anyone can find out where, and it's just text (not a picture) I'd be happy to edit that too. Let me know if you run into issues with the translated text, and I'll try to help or fix what I can.
Links:
Mega
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Installation Instructions:
Open Folder GAMEFOLDER \NtrLoopC_Data\StreamingAssets\
Set Language in LanguageSettings.txt to English (Language=1)
Unzip/Overwrite the files in GAMEFOLDER \NtrLoopC_Data\StreamingAssets\