Based on the previous answer, I digged a little deeper myself and found some other interesting further data. The Mehl et al. paper is indeed great because it sampled naturally occurring speech occurring over several days. Previous research seems to rely mainly on speech sampled in specific situations. Nevertheless, the evidence seems to converge. I found two meta-analyses. One looks at gender-differences in talkativeness in kids and the other is about adults.
The main results:
- In adults (Leaper & Ayres, 2007), men were actually slightly more talkative (d=-.14)
- the talkativeness of men was higher in mixed-gender interactions (d=-.28) than in same-gender interactions (d=-.09), reflecting mens' attempts to dominate conversations with women?
- men were more also more talkative when discussing impersonal topics (d=-.79), whereas women were more talkative involving self-disclosure (d=.39), in line with gender norms
- In kids (Leaper & Smith, 2004) there was no overall difference in talkativeness (d=.07, n.s.)
- for younger children (<3years), girls were more talkative (d=.32), while there was no difference for kids aged 3-16 (d=.08), likely reflecting different language development speeds for boys and girls
All in all, the idea that there is a kernel of truth to the stereotype of woman being more talkative than men seems to be refuted.
References
Leaper, C., & Ayres, M. M. (2007). A meta-analytic review of gender variations in adults’ language use: Talkativeness, affiliative speech, and assertive speech. Personality and Social Psychology Review, 11, 328–363. doi:10.1177/1088868307302221
Leaper, C., & Smith, T. E. (2004). A Meta-Analytic Review of Gender Variations in Children’s Language Use: Talkativeness, Affiliative Speech, and Assertive Speech. Developmental Psychology, 40, 993–1027. doi:10.1037/0012-1649.40.6.993