Most objective indices for speech intelligibility are essentially based on studies of Western languages and not tonal languages like Chinese. Consequently, if speech intelligibility in an enclosure is satisfactory for English, it is not necessarily satisfactory for Chinese, orvice versa. In this research, the differences in intelligibility between English and Mandarin (a spoken language of Chinese) have been investigated by carrying out a series of articulation tests in a long corridor and a regularly shaped (i.e., quasi-cubic) seminar room, using loudspeaker sources. The results suggest that in terms of speech intelligibility, Mandarin is slightly better than English under reverberant conditions, and English is considerably better than Mandarin under noisy conditions.