For words that only have three letters, there is no 4th letter. One example is with the word “incorporate”, there are no far more letters afterwards and therefore must be the word "increase". The word “addict” is from the BIP39 wordlist but you might have used “addi” for “addict”. You https://allyourbookmarks.com/story18916144/new-step-by-step-map-for-bip39-english-words