The multilingual feature wasn't really something I needed to add at this point, but I assumed Cursor would be able to easily set it up. However, out of the two methods Cursor recommended (i18next and next-intl), I chose next-intl and ended up mixing the two. This was confirmed while editing the multilingual version: Cursor set the i18next method as the main method, and when I requested a modification, it considered next-intl and made the modification, causing problems. Ultimately, I settled on i18next, but it was the first time I'd seen such a tangled code, and it was a strange(?) experience. Everyone, be careful.