Spotify Dedup supports now 4 languages: English, Spanish, German, and Portuguese. You can switch between them from the footer of the page.

I have done my best to get accurate translations but if you spot any issue please reach out to me on Buy Me a Coffee or Twitter (@jmperezperez). Likewise if you would like Dedup to be in your language, ping me. There has been a lot  of work behind the scenes to make i18n a part of the project, decoupled from the logic that performs the deduplication.