For words that only have three letters, there isn't any 4th letter. Such as with the word “include”, there aren't any far more letters afterwards and therefore has to be the word "increase". The word “addict” is while in the BIP39 wordlist but you might have utilized “addi” for “addict”. https://wise-social.com/story4285997/a-review-of-bip39-phrase-list