The use of prepositions is one of the most difficult grammar topics for Spanish learners. The high frequency prepositions ‘a’ (‘to, at, on’), ‘de’ (‘from, of’) and ‘en’ (‘in, on, into’) are often confused or omitted, especially in motion verb constructions (e.g., Campillos Llanos, 2014). This can be due to their polysemous character and the low salience. In addition, crosslinguistic influence (Jarvis and Pavlenko, 2008) from the first language as well as additional acquired foreign language(s) play a significant role.In order to analyse the complexity of interlanguage phenomena in the construction [motion verb + a/de/en + noun] to improve acquisition in Spanish classes, it is necessary to study authentic learner data. In this paper, I will discuss the results of an explorative pilot study on crosslinguistic influence carried out at a German grammar school in the federal state Baden-Württemberg in order to find out after which verbs of motion these prepositions are omitted or confused, how often this occurs, and which languages might influence it. The results of two groups of pupils at beginner level with the mean age of 14,03 are compared: The first group (n = 21) learns Spanish as the third foreign language, in addition to English and French, while the second group (n = 16) learns Spanish as the second foreign language after English. Both groups learn the named foreign languages in an instructed setting at school.The pilot study reveals that the prepositions ‘a’ and ‘de’ are much more often confused or omitted in the construction types [llegar/volver/venir + a + noun] (‘arrive/come back/come + to/in + noun’) and [salir/ir + de + noun] (‘leave/go + noun’) compared to [ir + a + noun] (‘go to + noun’). A possible explanation is positive and negative intra- and interlingual transfer of equivalent constructions from different languages. These results form a hypothesis basis that a systematic application of Pedagogical Construction Grammar (Boas, 2022; De Knop and Gilquin, 2016) and multilingual didactics (Fäcke and Meiβner, 2019; García et al., 2020) in Spanish classes to teach these polysemous prepositions could probably be helpful to avoid errors.