For words that only have 3 letters, there's no 4th letter. By way of example with the word “include”, there isn't any far more letters Later on and therefore should be the word "add". The word “addict” is inside the BIP39 wordlist however, you might have applied “addi” for “addict”. https://bookmarkshome.com/story4436662/not-known-facts-about-bip39-english-words