Bip39 Checksum. Whilst there are BIP39 wordlists in languages apart from English, it can be strongly not suggested to make use of non-English words for wallet backups. It might make restoring the wallet tricky or not possible. No, there isn't any complex limit towards the length of one's passphrase. On https://socialexpresions.com/story4690661/bip39-words-https-linktr-ee-bip39-top-guidelines-of-bip39-passphrase