For words that only have 3 letters, there isn't a 4th letter. As an example with the word “increase”, there won't be any a lot more letters Later on and thus needs to be the word "insert". The word “addict” is inside the BIP39 wordlist however , you would have https://naturalbookmarks.com/story18897298/bip39-phrase-generator-can-be-fun-for-anyone