Short answers, pulled from the story.
The lungs generate airflow and air pressure that moves upward into the larynx where vocal folds vibrate to create audible pulses. Muscles within the larynx adjust the length and tension of these folds to fine-tune pitch and tone while articulators filter the raw sound through the tongue, palate, cheek, and lips.
Adult male vocal folds measure between 17 mm and 25 mm in length while female folds range from 12.5 mm to 17.5 mm. This size difference creates distinct pitch ranges for men and women across most populations with men generally possessing a larger vocal tract that gives their voices a lower-sounding timbre independent of fold size.
Children learn to modulate vocal parameters consistently during speech before reaching the age of two years old. They listen to adult voices that differ significantly from their own to master these distinctions and develop the ability to vary abductory adduction of the vocal folds which has a strong genetic component linked to life preservation.
Speech pathologists identify four specific vocal registers based on laryngeal function including vocal fry and modal types. Singers utilize the singer formant to carry voice better over musical accompaniment beyond normal instrument frequencies while seven areas serve as possible vocal resonators ranging from lowest to highest within the body structure.
Talking improperly for long periods causes vocal loading which inflicts stress upon the speech organs and repeated abuse results in soft swollen spots that develop into harder callous-like nodules. Most polyps are larger than nodules and may require surgical removal due to single occurrence events while hoarseness or breathiness lasting more than two weeks indicates an underlying disorder such as nodes or polyps requiring medical investigation.