Color-codes words in Duolingo or translate-jokes by grammatical gender in target-to-source sentence challenges. Source information comes from:
Sentence translation example (en-pt):
Multiple choice exercise example (en-es):
You will need to have installed Greasemonkey on Firefox or Tampermonkey on Chrome. Then go to the userscript and click on "raw".
Currently follows the convention:
Gendered pronouns, which do not have hints in Duolingo, are colored--if the pronoun is unambiguous--in French, Portuguese, Spanish, German and Dutch. This means that in German, only er, ihn, ihrer, and es are colored. Der, for example, cannot be colored, since it could be masculine in the nominativ case, or feminine in the dativ case. In the future, I hope to be able to analyze case to disambiguate those pronouns' gender.