Why is the speed of each language so slow?

This is related to the information density of language. Scientists have done experiments. China people speak about 5. 142 syllables per second, which is the slowest, so they have the most useful information per second, and the information density ranks first at 0.94. Japanese people speak about 7.6 syllables per second, and the information density is only 0.46, so they speak faster.