Vocal cords (also known as vocal folds) are specialized tissues located within the larynx, commonly known as the voice box. They are responsible for producing sound through vibration as air passes between them. They are central to human communication, allowing for speaking, singing, and various other vocalizations. This article explores the development of vocal cords from early life through adulthood and old age.
The Blueprint in Early Development
Vocal cord development begins early in human embryonic growth. The initial formation of the larynx, which houses the vocal cords, starts around the third to fourth week of gestation. During this period, a structure known as the laryngeal prominence begins to emerge. By the fourth to sixth week, the precursors that will eventually become the vocal cords start to differentiate.
The vocal cords begin to take on a more defined shape between seven and ten weeks of gestation. Around the tenth to twelfth week, the true and false vocal folds become distinguishable. By the fifteenth to twentieth week of pregnancy, these structures are largely formed. Though developing, they cannot produce sound until after birth.
Voice Emergence in Infancy and Childhood
At birth, a baby’s vocal cords are present but are still quite immature, measuring approximately 2.5 to 3 millimeters in length. The larynx in newborns is positioned higher in the neck, typically between the C1 and C4 vertebrae. This higher position allows infants to breathe and swallow simultaneously. Over the first few years of life, the larynx gradually descends, reaching its adult position between the C4 and C7 vertebrae by around six to nine years of age.
As infants grow, their vocal cords undergo significant changes, lengthening to about 6 to 8 millimeters by age five and reaching approximately 7.5 millimeters by age seven. This growth contributes to the expanding range of sounds infants produce, from varied cries to babbling. The development of muscle control and coordination with breathing during this period enables the emergence of spoken language. An immature ligamentous structure appears in the vocal cords between one and four years.
Adolescent Voice Transformation
Adolescence marks a period of profound voice transformation, commonly recognized as the “voice break.” This change is primarily driven by hormonal shifts, particularly increased testosterone in males. During this time, the larynx experiences rapid growth, which is significantly more pronounced in males and results in the visible protrusion known as the Adam’s apple.
The vocal cords lengthen and thicken considerably. Male vocal cords can reach an average length of 1.6 centimeters, causing their voice to drop by approximately an octave. Female vocal cords also lengthen, reaching about 1.0 centimeter, and their pitch typically lowers by around three to four semitones. Adult vocal pitch is typically achieved two to three years after puberty, with stabilization continuing until around 21 to 25 years of age. Temporary voice cracking or instability is a normal part of this adjustive phase.
Lifelong Adaptations and Maintenance
Vocal cords remain dynamic structures that continue to adapt throughout adulthood and into advanced age. The cartilages supporting the larynx can begin to harden, a process called ossification, starting around 18 to 20 years in males and 22 years in females. Ossification increases after the third decade of life.
With increasing age, vocal cords can experience changes such as a loss of muscle tone, elasticity, and moisture. These natural processes can lead to subtle shifts in voice quality, including changes in pitch—often higher in older men and lower in older women—and a potentially weaker, breathier, or less steady sound.