Bip39 Dictionary. Whilst you can find BIP39 wordlists in languages in addition to English, it truly is strongly not encouraged to implement non-English words for wallet backups. It might make restoring the wallet complicated or unachievable. BIP39 specifies a list of 2048 words from which the mnemonic phrase is chosen. https://onelifesocial.com/story4270526/bip39-https-linktr-ee-bip39-about-ian-coleman-bip39