Bip39 Standard. Though there are actually BIP39 wordlists in languages other than English, it truly is strongly not advisable to work with non-English words for wallet backups. It'd make restoring the wallet complicated or not possible. This works simply because BIP39 is supported by a great number of wallet brands. https://socialmediatotal.com/story4106703/bip-39-https-linktr-ee-bip39-not-known-details-about-bip39-list