For words that have only 3 letters, there's no 4th letter. Such as with the word “increase”, there aren't any more letters Later on and therefore has to be the word "include". The word “addict” is within the BIP39 wordlist but you would've used “addi” for “addict”. Stability: Anybody with https://total-bookmark.com/story18908766/5-simple-techniques-for-bip39-seed-phrase