For words that only have 3 letters, there is absolutely no 4th letter. Such as with the word “increase”, there isn't any a lot more letters afterwards and so need to be the word "incorporate". The word “addict” is within the BIP39 wordlist but you might have utilized “addi” for https://socialfactories.com/story4268734/not-known-facts-about-bip39-english-words