For words that only have 3 letters, there is not any 4th letter. For instance with the word “add”, there are no much more letters Later on and thus must be the word "increase". The word “addict” is from the BIP39 wordlist but you might have used “addi” for “addict”. https://telebookmarks.com/story9085956/examine-this-report-on-bip39-mnemonic-phrase-tool