For words that only have three letters, there's no 4th letter. For instance with the word “add”, there won't be any a lot more letters Later on and thus need to be the word "incorporate". The word “addict” is from the BIP39 wordlist but you might have used “addi” for https://blogfreely.net/travenmdoq/h1-b-bip39-word-listing-explained-your-important-source-for-creating-secure