Abstract: This paper evaluates taps and trills [r] of Spanish and Persian languages. Taps contain one vibration while trills have several vibrations. Thus, the differences between taps and trills are related to how they are pronounced with regard to their environment and position. As the noteworthy exceptions of opposite rhotic phonemes are Spanish and Persian languages, the study work on probable differences between opposite rhotic phonemes in these two languages. Analyzing different examples from both languages, the study argues that Spanish taps and trills [r] differ in the intervocalic position within the word, while Persian taps and trills [r] don‟t make such differences. Moreover, the study shows that pronouncing taps and trills interchangeably alters the meaning of words in Spain, though it is not the case in Persian.