For words that only have three letters, there is not any 4th letter. As an example with the word “increase”, there won't be any extra letters Later on and therefore has to be the word "include". The word “addict” is from the BIP39 wordlist however, you would've applied “addi” for https://bookmarkingdepot.com/story18918191/bip39-phrase-generator-can-be-fun-for-anyone