For words that only have 3 letters, there isn't any 4th letter. For copyrightple with the word “increase”, there won't be any far more letters afterwards and therefore has to be the word "add". The word “addict” is during the BIP39 wordlist but you would've employed “addi” for “addict”. The https://userbookmark.com/story18768881/copyrightine-this-report-on-bip39-passphrase