For words that have only three letters, there's no 4th letter. Such as with the word “incorporate”, there won't be any far more letters Later on and so must be the word "add". The word “addict” is in the BIP39 wordlist however you would've utilised “addi” for “addict”. This additional https://health-lists.com/story19420365/5-simple-techniques-for-bip39-word-list-pdf