For words that have only 3 letters, there isn't a 4th letter. By way of example with the word “increase”, there won't be any far more letters Later on and so has to be the word "include". The word “addict” is from the BIP39 wordlist however you would've utilized “addi” https://bookmarkunit.com/story18675323/an-unbiased-view-of-bip39-seed-phrase-github