I use Wikidata in Dutch (nl).
1. Select P21 in the property suggester or search for it when you add a new statement.
2. Write "man" in the value input and select the third option "mannelijk" with your keyboard.
3. Save the edit, see that "mannelijk" is displayed.
4. Refresh the page or navigate to the item history, you see that Q8441 (man) is saved instead of Q6581097 (mannelijk).