The relationship between the distribution of continuous silence and voicing periods accumulated (duration of continuous voiced and unvoiced segments of 0.05 s) by teachers teaching in classrooms with different reverberation time (RT) was examined. Understanding the distributions of these accumulations and the relationship with the RT has implications on potential vocal fatigue risk factors and it can be a useful information for clinicians. Twenty-two primary school teachers were monitored over 1 or 2 four-hour workdays with the Ambulatory Phonation Monitor. The RT ranged between 0.58 s and 1.58 s, with a median equal to 0.9 s. The classrooms were classified as low RT (0.58 s < RT < 0.90 s) and high RT (0.90 s ≤ RT < 1.58 s). The values of silence accumulation in low RT classrooms were significantly shorter than the accumulation in high RT classrooms in almost the whole range of accumulation periods (0.2 s—10 s). The difference was negligible for time shorter than 1.5 s and longer than 8 s. The values of voice accumulation in low RT classrooms are significantly shorter than the accumulation in high RT classrooms in almost the whole range of accumulation periods (0.2 s—1.31 s).