The infrahyoid muscles and the isthmus of the thyroid are positioned out of the way to make an opening in the trachea. The laryngeal muscles are the means of closing the glottis in swallowing and speech. The extrinsic muscles move the larynx, e.g., elevate during swallowing, and the intrinsic muscles affect the length, position, and tension of the vocal cords. If the cords are taut, then the pitch is higher. Less tension, lower pitch.
Males have thicker cords and thus lower voices than females.
Of course, other parts of the head and neck assist in making speech. Vowel sounds are made by constriction of the pharyngeal walls. The sinuses act as resonating chambers. The lips and tongue also help to form words. Most of these cancers can be easily visualized, e.g., oral exam, laryngoscope.