The cases where we should create different Lexemes with the same lemma, language and lexical category are very rare (but exists). It's likely that people will create duplicates, especially since the search is not working well at the moment.

We should create a warning on Special:NewLexeme, when someone is about to create a Lexeme that has the exact same Lemma AND language AND lexical category than another existing Lexeme. This should be warning the user, giving him a link to the existing lexeme so they can check, but not block them in the process of creating the new lexeme.

This could be a pop-up or something else appearing when clicking on "Create", saying "A Lexeme with the same lemma, language and lexical category already exists: LXXX. (with a link on LXXX) If you still want to create the current Lexeme, click on Create to continue."