One of the most defining characteristics of a human is their voice: its pitch, how it resonates and of course, the vocal range. But where does it come from? How much are our voices genetic, and how much are they influenced by environmental factors like language and culture?
So far, there is little research on how much genetics contributes to our voice (Sataloff: 1995). Despite this, at least some of the vocal similarities between family members are suspected to come from shared DNA for laryngeal anatomy, as in every other physical characteristic (Kampwirth, 2013). Yet, as people who are related generally grow up together, it can be difficult to separate which factors have a genetic source, and which have an environmental source (University of Iowa).
Despite this however, one genetic difference clearly impacts the voice: sex. Males have larger vocal folds than females. This means that they typically have deeper voices than females even before adolescence. Stretched along the larynx (the voice box), when air is brought up from the lungs to speak, the vocal cords vibrate, thus creating sound. The length, size and tension among them determines their fundamental frequency, averaging at around 125 Hz in men, 210 Hz in women and around 300 Hz in children. The higher the fundamental frequency of a voice, the higher its pitch (Kampwirth, 2013).
The language we speak also seems to have a big impact on our voices. Studies on Cantonese and Mandarin speakers found that the native language of a person affects the fundamental frequency at which they distinguish, interpret and reproduce sounds. For example, Cantonese speakers are better able to produce tones commonly found in Cantonese than people who speak Mandarin are (Liu et al.: 2010). This suggests that our native language fundamentally shapes the way we can use our vocal cords, and thus how we can use our voices.
This is further supported by evidence from the University of Tampere, Finland. A study conducted in 2017, showed that people are more likely to achieve vocal fatigue when speaking a foreign language, as more mental and physical effort is required to produce foreign sounds than those they are used to in their native language (Javinen: 2017).
Our voices are also affected by other environmental factors. Emotional states are one example of this. When excited, nervous or frightened, the muscles supporting the larynx tend to contract involuntarily. This increased tension then produces a higher, unsteady pitch. Although temporary for as long as the emotional state exists, it may go some way to explain why voices differ between different cultures. For example, calmer, more introverted cultures such as those in Scandinavia, may generally have a softer tone, whereas those in more extroverted environments such as in Latin America, may access emotions such as excitement, nervousness and fright more frequently, and thus have a different tone, or voice.
Health is also an important factor when determining the sound of a voice. For example, a cold virus causes vocal cords to swell, meaning they rub together and rasp our speech. Likewise, pollution, an overly dry climate, smoking, drinking alcohol and shouting too much also affect the voice by straining the larynx.
Age is also a factor that puts strain on the vocal cords. Over time, the vocal cords and their surrounding muscles lose their strength and elasticity, with their mucus membranes becoming thinner and drier. These physical changes lead to elderly voices generally having a lower volume, shakiness and less endurance.
To conclude, although it is uncertain how much genetics contributes to our voice, genetics definitely play a role at least in the structure of our larynx and vocal cords, as well as our sex. Yet, environmental differences seem to play a large role in how they’re defined too. From native language and culture to illness and age, when taken together, these factors may arguably have an even larger role in defining our voices than our genetics.