For words that only have 3 letters, there's no 4th letter. As an example with the word “include”, there are no additional letters Later on and therefore should be the word "insert". The word “addict” is while in the BIP39 wordlist however, you would have used “addi” for “addict”. You https://remingtonnjdi433.wordpress.com/2025/01/17/opening-the-world-of-bip39-a-comprehensive-overview-to-mnemonic-expressions-and-word-lists/