That depends on what you mean by "efficiency". The most natural understanding of the question for me would be to look at the information density of spoken langu

That depends on what you mean by "efficiency". The most natural understanding of the question for me would be to look at the information density of spoken language with respect to time, as was done in [1]. The linked findings looked at 7 different languages and found that all of the studied languages had about the same rate. However, the languages vary significantly in the density of information with respect to syllables, and the speed at which syllables are produced. EDIT: chart on page 7 (544) [1]https://muse.jhu.edu/article/449938/pdf https://muse.jhu.edu/article/449938/pdf