Slower men, who at their worst hit a rate of 4.87 syllables per second, notched up fewer than two.
Women with less breathy voices, and a shorter speech duration, had fewer sexual partners compared to more breathy women.
The study, published in the journal Evolution and Human Behavior, was led by Alexandre Suire of the University of Montpellier in France.
He said: 'Men displaying faster articulation rate and relatively louder voice in this study had higher previous success with women. These men would presumably feel more self-assured when placed in a mating or competitive context.
"This self-confidence may have relaxed male subjects, stabilising their tempo and vocal intensity across speech. If so, this suggests that when men feel confident, they speak with faster and louder speech."