For words that have only 3 letters, there isn't any 4th letter. For example with the word “increase”, there isn't any more letters afterwards and so have to be the word "increase". The word “addict” is inside the BIP39 wordlist however you might have applied “addi” for “addict”. Finding a https://dailybookmarkhit.com/story18876808/helping-the-others-realize-the-advantages-of-bip39-mnemonic-phrase-tool