Speech carries a wealth of information about the speaker aside from any verbal message ranging from emotional state (sad, happy, bored, etc.) to illness (e.g., cold). Central features are a speaker’s gender and their sexual orientation. In part this is an inevitable product of differences in speakers’ anatomical dimensions, for example on average males have lower pitched voices than females due to longer, thicker vocal cords that vibrate more slowly. Arguably much more information has been learned by a speaker as they construct their gender or identify with a particular sexual orientation. Differences in speech already begin in young children, before any marked gender-related anatomical differences develop, emphasizing the importance of behavioral patterns. Gender, gender identity, and sexual orientation are encoded in speech in a range of different phonetic parameters relating to both phonation (activity of the vocal folds) and articulation (dimensions and configuration of the supraglottal cavities), as well as the use of pitch patterns and differences in voice quality (the way in which the vocal folds vibrate). Differences in the size and configuration of the supraglottal cavities give rise to differences in the size of the acoustic vowel space as well as subtle differences in the production of individual sounds, such as the sibilant [s]. Furthermore, significant and systematic gender-specific differences have been found in the average duration of utterances and individual sounds, which in turn have been found to have a complex relationship to the perception of tempo.