Project Summary Transgender (TG; gender identity does not match sex-assigned at birth) individuals are underserved, targets of violence, and at higher risk for negative health outcomes. Many TG individuals report that producing a voice congruent with their gender identity is crucial to affirming their gender identity. There are a variety of gender affirming services available, but medical interventions, such as surgery or hormones do not do not ensure satisfaction with vocal gender. Voice modification is often the preferred intervention. One of the primary goals for voice modification is to alter fundamental frequency (fo) towards sex-normative values, but little is known about the underlying changes to vocalization required to habituate a desired fo. Research suggests that the compensatory strategies used by TG individuals to attain a desired fo are characterized by atypical patterns of vocalization, consistent with vocal hyperfunction (VH). This may explain the high frequency of vocal complaints in TG speakers. In sum, despite a critical health need in an at-risk population, there is a gap in the rigor of the prior research, with a lack of evidence identifying changes in the subsystems of voice production between the habitual and desired fo of TG individuals. Therefore, the goal of this proposal is to evaluate our conceptual model of voice modification: 1) that altering fo to be more gender congruent will result in less efficient vocalization, thus increasing signs of VH; and 2) the magnitude of the change in fo required to achieve vocal gender satisfaction will correspond to the magnitude of change in measures of VH. This observational study will measure VH in TG adults who are not satisfied with their habitual voice and desire a more gender- congruent voice. Only TG individuals who have expressed a desire to change their fo to become more gender congruent will be recruited for this study. In Aim 1, we will collect respiratory kinematic, acoustic, aerodynamic, laryngoscopic, self-perceived, and listener auditory-perceptual measures of VH when individuals produce their habitual and desired fo. This aim will identify the compensatory strategies used by TG individuals to alter their fo. Aim 2 will examine the relationship between the desired change in vocal gender needed to achieve satisfaction and the degree of change in measures of VH necessary to produce a desired fo. This aim will identify the relationship between vocal gender satisfaction and the compensatory strategies used when producing a desired fo. Together, these aims will provide a roadmap for future evidence-based treatment: clinicians will gain baseline information about vocal function within the TG population, which is critical for providing evidence-based assessment and treatment of voice disorders.