For words that only have 3 letters, there isn't a 4th letter. For instance with the word “insert”, there won't be any far more letters Later on and therefore must be the word "incorporate". The word “addict” is within the BIP39 wordlist but you would have used “addi” for “addict”. https://bookmarkrange.com/story20474655/how-much-you-need-to-expect-you-ll-pay-for-a-good-valid-bip39-seed-phrase