Short answers, pulled from the story.
Male vocal folds measure between 17 mm and 25 mm in length. Female vocal folds are shorter, ranging from 12.5 mm to 17.5 mm. This size difference is a primary reason men and women have differently pitched voices.
Speech pathologists recognize four vocal registers based on laryngeal physiology: the vocal fry register, the modal register, the falsetto register, and the whistle register. Each register corresponds to a distinct vibratory pattern of the vocal folds and a characteristic range of pitches.
The singer's formant is a resonance that trained singers add above the frequency range of most orchestral instruments. Because it occupies a higher frequency band than the accompanying instruments, it allows a singer's voice to carry over musical accompaniment without amplification.
Vocal nodules are caused by repeated misuse of the vocal folds over time, beginning as soft swollen spots that harden into callous-like growths. Speech-language therapy addresses them by teaching patients to eliminate irritation through habit changes and vocal hygiene, with prevention considered the best approach.
The seven areas that can act as vocal resonators are, from lowest to highest in the body: the chest, the tracheal tree, the larynx, the pharynx, the oral cavity, the nasal cavity, and the sinuses. Sound passing through these air-filled cavities is enhanced in timbre and intensity.
A 2021 study published in the Journal of Neuroscience found peaks in acoustic energy in recorded speech samples that mirror the distances between notes in the twelve-tone musical scale. The researchers proposed that the scale may have evolutionary roots in the sound of the human voice.