The relationship among syllable articulation ,sentence intelligibility and physical indicator in rooms has not been discussed. And the contribution of context effect on speech intelligibility has not been estimated. So, we carried out speech intelligibility tests in experimental sound fields under noise and reverberation. The result of this paper are as follows ; l) The tendency of speech intelligibility is different from syllable articulation in noise and reverberation fields. 2) There is possibility of using sentence material evaluating better than syllable one. 3) Speech Transmission Index is unsuitable for evaluating speech intelligibility.