This study focuses on an unexplored aspect of the performance of algorithms for blind reverberation time (T) estimationon the effect that speech signal's phonetic content has on the value of the estimate of T that is obtained from the reverberant version of that signal. To this end, the performance of three algorithms is assessed on a set of logatome recordings artificially reverberated with room impulse responses from four rooms, with their T 20 value in the [0.18, 0.55] s interval. Analyses of variance showed that the null hypotheses of equal means of estimation errors can be rejected at the significance level of 0.05 for the interaction terms between the factors "vowel", "consonant", and "room", while the results of Tukey's multiple comparison procedure revealed that there are both some similarities in the behaviour of the algorithms and some differences, where the latter are stemming from the differences in the details of algorithms' implementation such as the number of frequency bands and whether T is estimated continuously or only on the selected, the so-called speech decay, segments of the signal.