Whenever a checksum is invalid, alert the person the phrase is just not anything generated by your application, and talk to when they want to use it in any case. Using this method, your application only must maintain the wordlists for your supported languages, however you can recover phrases made https://wise-social.com/story4430492/the-fact-about-bip39-seed-phrase-word-list-that-no-one-is-suggesting