For words that only have 3 letters, there is absolutely no 4th letter. By way of example with the word “include”, there isn't any a lot more letters Later on and therefore needs to be the word "incorporate". The word “addict” is inside the BIP39 wordlist but you would have https://binksites.com/story8524737/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator