Taiwanese, a variety of Southern Min, is a dialect spoken in Taiwan with a pervasive tone sandhi system. To speak Taiwanese fluently and appropriately, one has to frequently apply Taiwanese tone sandhi. While it is common knowledge that tone sandhi is pervasive in spoken Taiwanese, there are no studies reporting on the rate of Taiwanese tone sandhi in spoken corpora in any genre. This paper attempts to determine the average tone sandhi rates of L1 Taiwanese dominant speakers and L1 Taiwanese L2 Mandarin bilinguals by analyzing a spoken corpus. Our study shows that the two groups do not reveal any significant differences in their tone sandhi application rate. On average, out of every 100 syllables, approximately 67 syllables have undergone tone sandhi. Regarding the application rates of individual tone sandhi rules, all speakers show a consistency as to which rules are most common and which are not. Consequently, one implication of our study is that L2 Mandarin fluency does not impact L1 Taiwanese tone sandhi frequency. Other implications help make clear the specific nature of the Taiwanese tone sandhi system.