For words that only have 3 letters, there is no 4th letter. Such as with the word “increase”, there aren't any a lot more letters Later on and thus should be the word "insert". The word “addict” is from the BIP39 wordlist but you would've utilised “addi” for “addict”. To https://dmozbookmark.com/story19173562/facts-about-bip39-seed-phrase-github-revealed