For words that only have 3 letters, there is no 4th letter. Such as with the word “incorporate”, there are no a lot more letters Later on and therefore must be the word "insert". The word “addict” is within the BIP39 wordlist however you might have utilized “addi” for “addict”. https://socialbookmarkgs.com/story18999233/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator