Am I certified by the famous Goethe-Institut?
Teaching a subject requires two things. Knowledge of the subject matter and knowledge of pedagogy / theories of learning / teaching techniques etc. But depending on your audience the importance of these two vary. When teaching school children it is paramount to keep them motivated and the actual material thought is rather sparse. When one teaches adult academics who study out of their own choice and who have already built some intellectual capabilities, then such concerns become less relevant.
The curricula of the various certifications of the Goethe Institut is heavily biased towards the study of education. Grammar and other linguistic topics hardly play a role. Therefore I chose not to pursue a certificate by the Goethe Institut.