For words that have only three letters, there isn't a 4th letter. Such as with the word “include”, there aren't any additional letters Later on and therefore needs to be the word "increase". The word “addict” is from the BIP39 wordlist but you would've used “addi” for “addict”. In the https://bookmarkproduct.com/story18896335/a-review-of-bip39-passphrase