“…This is because children with mental retardation have difficulty using functional words, which in this case are prepositions. In connection with difficulties in particle production, research by Christou, Guerra, Coloma, Andreu Barrachina, Araya, Rodriguez-Ferreiro,… Sanz-Torrent (2020) shows that there are different developmental trajectories in groups of people with language development disorders, however, regardless of the group of sufferers mental disorders in producing particles, it seems that they can understand the particles in the current experimental conditions. That is, there is still hope to mediate how children with mental retardation can understand the use of functional language such as particles, prepositions, articles, conjunctions, and interjections, and this -understanding the use of functional language -must be continuously experienced by the children.…”