For words that only have three letters, there isn't a 4th letter. For example with the word “increase”, there isn't any far more letters Later on and thus must be the word "increase". The word “addict” is while in the BIP39 wordlist however, you would have utilized “addi” for “addict”. https://hindibookmark.com/story20530241/the-greatest-guide-to-seed-phrase-bip39