Ikuko Patricia Yuasa's Culture and gender of voice pitch provides a comparative sociophonetic analysis of pitch in conversational interactions among speakers of Japanese and American English. Unsurprisingly, members of both of these groups make use of pitch as a highly salient cue for indexing gender; however, as a good deal of previous research has shown, the precise nature of this differentiation varies across the two languages. Prior accounts of the differences between these broad cultural groups have suggested that Japanese women generally speak in a higher pitch than American women, while Japanese men conversely use a lower pitch than their American counterparts. Yuasa, however, presents a more complex analysis by incorporating the role of politeness and familiarity between interlocutors into her research design.

In addition to comparing a group of Japanese and American women and men as they conversed with familiar interlocutors of the same gender, Yuasa also examined how Japanese speakers used pitch when conversing with familiar versus unfamiliar individuals. At first glance her cross-cultural findings look quite similar to previous research: Japanese women made use of a higher mean pitch than American women; Japanese men made use of a lower mean pitch than American men; and Japanese speakers of both genders used a wider pitch range than Americans as well as employing more dramatic intonational shifts. However, Japanese speakers' pitch ranges look quite different in talk with unfamiliar co-participants, in which case they are much narrower. Furthermore, while dramatic shifts in pitch within intonational units were used primarily by women among the American English speakers, such shifts were used by Japanese women and men alike in the familiar conversational context. In one case, Yuasa is able to show how two sentences that are nearly identical semantically and structurally were produced with significantly different pitch ranges by the same male speaker based on his familiarity with his interlocutor.

One of the primary foci of Yuasa's book is the relationship between pitch and emotional affect. Quite a bit of work has shown that particular emotions are strongly associated with expansions in pitch range, particularly states of emotional excitement and those described as “elation” in the phonetic literature. However, as Yuasa details, Japanese cultural norms tightly limit the expression of such emotions in nonintimate relationships. As a result, a restricted pitch range is more appropriate for Japanese speakers in unfamiliar contexts, regardless of gender. A wide pitch range can thus serve as a resource for the creation of solidarity between speakers, which is tied closely to what are often referred to as positive politeness strategies. Yuasa argues that the association between American women and collaborative interactional styles, which often emphasize intimacy through positive politeness, can explain the ideological connection that exists between femininity and large pitch ranges among English speakers despite empirical challenges to this association. Japanese speakers, by contrast, can be seen to use quite large pitch ranges in familiar contexts regardless of gender, which demonstrates the socially constructed and culturally variable nature of gendered differences in the voice.