Wie muss ich meine Sprachkenntnisse nachweisen?
If you hold a German degree, you have to demonstrate evidence of an adequate level of Spanish or Portuguese language proficiency at least at the B2 GER level. The proof nust explicitly state the level you are at and must be submitted along with the rest of application documents.
If you completed a degree in a different country than Germany, the university entrance qualification might as well count as the certification of your Portuguese or Spanish skills, if it was completed in a Spanish or Portuguese speaking university. Additionally, you have to demonstrate your language proficiency in German. A proof of German proficiency at the B2 GER level must also be submitted with the application.