Voice and Communication Therapy for Clients Who Are Transgender/Transsexual
The American Speech-Language-Hearing Association (ASHA) is the national professional, scientific, and credentialing association for 182,000 members and affiliates who are audiologists; speech-language pathologists; speech, language, and hearing scientists; audiology and speech-language pathology support personnel; and students.
Wikipedia: Voice therapy (transgender)
Voice therapy or voice training refers to any non-surgical technique used to improve or modify the human voice. Because voice is a gender cue, trans women frequently undertake voice therapy as a part of gender transition in order to make their voices sound female, and therefore increase their readability as females in society. Transgender people and crossdressers who present as women may also desire to feminize their voices and therefore undertake voice therapy.