For words that have only 3 letters, there isn't any 4th letter. For example with the word “insert”, there isn't any far more letters Later on and therefore must be the word "add". The word “addict” is from the BIP39 wordlist but you might have made use of “addi” for https://getidealist.com/story20655765/helping-the-others-realize-the-advantages-of-bip39-seed-phrase-mnemonics-generator