This research aims to describe the beliefs of the students of the courses German 2, 3 and Semillero program at Pontificia Universidad Javeriana regarding the learning of the foreign language mentioned above, while taking into account three specific deviations of its grammar: cases, genres and declension. The main objective of the research was to define how beliefs influenced the learning process, as well as to describe and identify the origin of these beliefs mainly considering the students context. All of the above arises from the interest to explore how beliefs can change a perception and also how they come to affect the learning process of a foreign language, in this particular case about German being that it is perceived in most cases to have a complex and difficult learning. Several studies show nowadays that beliefs take a key role in the learning of a foreign language. The theoretical framework of this research held authors such as Barcelos and Kalaja (2006), Richards and Lockhart (1994) and Horwitz (2015) who show that learning is ruled mostly by the beliefs that students carry about a language in particular. On the other hand, the concept of Linguistic Interference (language transfer) is addressed, due to the fact that from its meaning, the differences between German and Spanish were able to be identified and also to notice how they were related to the beliefs surrounding the students learning process. The last concept taken was cases, genre and declension. On the basis of the foregoing, it is appropriate to mention that this research used a quantitive as well as qualitive method, since three instruments were chosen for data collection: first, the BALLI questionnaire proposed by Horwitz had an adequate adaptation to the research. In the second instance, a focus group was held with students from the Semillero and, finally, semi-structured interviews were created in order to provide answers to the main research question, after relating them to the proposed theory. The results show that both own experiences and beliefs that have been socially constructed are essential to establish a conception about German as a foreign language in a Spanish-speaking context. In addition, it was found that motivation is vital for a continuous learning process.