Bip39. Despite the fact that there are actually BIP39 wordlists in languages in addition to English, it's strongly not advisable to employ non-English words for wallet backups. It might make restoring the wallet challenging or unachievable. Without having a passphrase, your funds are only as secure as your seed phrase. https://infopagex.com/story4496736/bip39-passphrase-https-linktr-ee-bip39-not-known-factual-statements-about-ian-coleman-bip39