For words that only have 3 letters, there isn't a 4th letter. Such as with the word “incorporate”, there isn't any a lot more letters Later on and therefore need to be the word "incorporate". The word “addict” is from the BIP39 wordlist however you would've applied “addi” for “addict”. https://hotbookmarkings.com/story18884561/invalid-bip39-phrase-things-to-know-before-you-buy