For words that have only three letters, there isn't a 4th letter. By way of example with the word “insert”, there won't be any additional letters Later on and therefore should be the word "add". The word “addict” is in the BIP39 wordlist but you might have applied “addi” for https://hyperbookmarks.com/story18981190/top-guidelines-of-bip39-word-list-pdf