Women in almost every culture speak in deeper voices than Japanese women. American women’s voices are lower than Japanese women’s, Swedish women’s are lower than American’s, and Dutch women’s are lower than Swedish women’s. Vocal difference is one way of expressing social difference, so that in Dutch society, which doesn’t differentiate much between its image of the ideal male and the ideal female, there are few differences between male and female voice. The Dutch also find medium and low pitch more attractive than high pitch.
That is from the new and interesting The Human Voice: How this Extraordinary Instrument Reveals Essential Clues About Who We Are, by Anne Karpf. Here is an interesting dissertation abstract on voice pitch, some of which relates to economic ideas on signaling.