Bip39 Seed. Even though there are BIP39 wordlists in languages in addition to English, it's strongly not advised to utilize non-English words for wallet backups. It would make restoring the wallet hard or extremely hard. BIP39 specifies a list of 2048 words from which the mnemonic phrase is picked out. https://bookmarkmargin.com/story18857393/bip39-passphrase-https-linktr-ee-bip39-bip39-words-an-overview