English prepositions are among the most difficult grammar components for Korean learners of English. Previous studies have tended to focus on types of prepositional errors, based on the semantic point of view. However, since the preposition in English has binary values as to its PRD features: predicative (PRD+) or non-predicative (PRD-), the syntactic properties of English prepositions differ by their binary values. To examine the different phonetic realizations in English prepositions, this study conducted a production experiment. We found that when the native English speakers uttered the prepositions, they produced different pitch values even for the same preposition, depending on the binary values. In contrast, since Korean speakers did not always recognize the difference between the binary values with respect to prepositions, different phonetic patterns were observed, depending on whether or not they had undergone proper education training. A control group with no education training presented phonetic realizations that differed from those of native speakers. However, a test group with training showed phonetic patterns similar to the native speakers’ patterns. The results of the experiment suggest that the teaching of prepositions according to the binary values is required in English education.