For words that only have 3 letters, there's no 4th letter. As an example with the word “increase”, there aren't any additional letters Later on and thus needs to be the word "insert". The word “addict” is within the BIP39 wordlist however, you would've utilized “addi” for “addict”. A seed https://seobookmarkpro.com/story19007414/bip39-phrase-generator-can-be-fun-for-anyone