For words that have only three letters, there's no 4th letter. As an example with the word “incorporate”, there won't be any far more letters afterwards and so needs to be the word "increase". The word “addict” is in the BIP39 wordlist however , you would have utilized “addi” for https://iowa-bookmarks.com/story14453127/getting-my-bip39-words-to-numbers-to-work