For words that have only three letters, there is not any 4th letter. Such as with the word “include”, there are no more letters Later on and therefore needs to be the word "insert". The word “addict” is from the BIP39 wordlist however, you would have employed “addi” for “addict”. https://wildbookmarks.com/story19154733/how-much-you-need-to-expect-you-ll-pay-for-a-good-valid-bip39-seed-phrase