For words that only have 3 letters, there's no 4th letter. Such as with the word “include”, there won't be any more letters Later on and therefore should be the word "insert". The word “addict” is within the BIP39 wordlist but you might have utilized “addi” for “addict”. Using BIP44 https://active-bookmarks.com/story18711035/the-2-minute-rule-for-bip39-all-words