Language has both literal and figurative types. In the education setting, it is common that the figurative one is the major language to convey certain connotative meanings. One of the instances of figurative language is idioms. However, still not many studies have examined the processing of idioms in monolinguals and bilinguals. Therefore, the present study intends to investigate the cognitive processing of idioms used by the bilingual population. The norming study was first conducted to gain normative data (familiarity, affective valence, frequency, imageability) of Dutch and Indonesian idioms. This is followed by the cognitive task using a lexical decision task to test the comprehension process and whether there are bilingual effects during the process. The preliminary results suggest that there is a bilingual effect on the comprehension processes of idioms where reaction times data and accuracy rates depict the results. As a basic research, the current study will provide the basis for further investigation on the use of Dutch-Indonesian idioms in a more experimental and/or applicative approach. In addition, in terms of the SDGs criteria, the study applies the relationship between language used to improve the quality of education specifically of the communication in the classroom setting.