For words that only have 3 letters, there is no 4th letter. For example with the word “add”, there are no a lot more letters Later on and therefore must be the word "add". The word “addict” is while in the BIP39 wordlist however, you would have utilised “addi” for https://getsocialnetwork.com/story4436838/invalid-bip39-phrase-things-to-know-before-you-buy