For words that only have three letters, there isn't any 4th letter. For instance with the word “add”, there isn't any more letters Later on and therefore should be the word "incorporate". The word “addict” is during the BIP39 wordlist but you might have utilised “addi” for “addict”. BIP39 and https://bookmarklogin.com/story18932055/the-greatest-guide-to-seed-phrase-bip39