The beauty of communication is often overlooked. Sometimes, it feels like a simple part of our daily routines, like saying “good morning” to a family member. Other times, we communicate in very subtle ways, like nodding our heads or using our car lights to signal a right-turn. With every method of communication, our intention is the same; to understand and to be understood. 

The ability to speak and develop language grants us the chance to express ourselves with ease. It allows toddlers to tell their parents that they are hungry or thirsty, and it allows adults to share information with their peers. Though there are plenty of methods of communication, speaking is generally the most efficient of them all.

The average adult may regard the act of speaking as a very simple, involuntary task, when in reality, it requires the simultaneous function of the brain and various organs of the vocal tract. 

The Anatomy of Speech 

The vocal tract includes the lips, teeth, alveolar ridge, nasal cavity, palate, uvula, tongue, pharynx, vocal cords, epiglottis and larynx. 

For every sound documented in the International Phonetic Alphabet (IPA), specific vocal tract organs act as articulators and position themselves in a way that can allow for airflow (such as in the case of vowels), or that can partially or completely obstruct airflow (such as in the case of consonants). With that said, in the sentence “the beauty of communication is often overlooked,” there are 37 distinct sounds, each of which require a different position of the vocal tract. Regardless of this fact, the average adult can repeat the phrase in a few seconds.

ðə ˈbjuːti ɒv kəˌmjuːnɪˈkeɪʃən ɪz ˈɒft(ə)n ˌəʊvəˈlʊkt

Figure 2: The phrase “The beauty of communication is often overlooked” translated into IPA. The symbols were copied and pasted using a tool from toPhonetics.com 

Aside from the anatomical process of speaking, there is still a mystery about language acquisition; how do we gain the ability to speak and develop a language? Intriguingly, the current body of evidence reports the FOXP2 gene as that of the first to have a clear role in language^1,2,3. 

The Contribution of Genetics to Language 

The human FOXP2 gene can be found on chromosome 7q31². It is included in the 5% most conserved genes², which demonstrates how important its function is. In general, essential genes need to have their sequences replicated faithfully to ensure proper function. Analysis of the FOXP2 gene in different organisms shows that a mutation causing a single amino acid change can transform its function completely. To illustrate, the FOXP2 protein of a chimpanzee differs from the mouse FOXP2 by 1 amino acid², and differs from the human FOXP2 by 2 amino acids². Therefore, it is critical that the FOXP2 gene should be replicated precisely as a single change can be the difference between being able to speak or not. 

Unfortunately, an individual with a FOXP2 mutation will present with a speech and language disorder that prevents them from effectively expressing themself. This was discovered following an investigation in 1990, when a family referred to as the “KE family” was interviewed about their condition and family history³. 

The discovery of FOXP2 and the effect of FOXP2 mutations

The observation that the KE family had multiple members affected by speech and language disorders gave the scientific community reason to suspect an underlying genetic cause. This prompted them to observe three generations of the KE family and once the pedigree was made, it was clear that the disorder followed an autosomal dominant pattern³; the suspected mutation was being passed on such that whoever had the mutation, expressed the disorder. While it was clear that the affected individuals were having difficulty communicating, specifying the source of the issue was not initially clear. Researchers questioned if their reduced ability to communicate was due to problems with grammar comprehension, phonological systems excluding grammar, or if the disorder was not localized to a specific region of the brain, and thus affected all systems responsible for language. By understanding the specific issue presented in affected individuals, and in what aspects they differ from unaffected individuals, phenotype designations were easier to make accurately. To determine how the KE family was different, the affected members were evaluated for pronunciation, grammar, semantics, verbal IQ and non-verbal IQ, and their performance was compared to the test results of unaffected individuals³. 

The assessments suggested that the affected members of the KE family were capable of understanding language, but struggled with producing it³. Overall, it was found that the greatest difference between affected and unaffected phenotypes was in word and nonword repetition and orofacial praxis³. Orofacial praxis describes the effective use of muscles associated with articulation, such that the speaker can communicate coherently. In the case of the KE family, the affected members could not verbally communicate because they had problems performing the movements necessary to speak. Once the phenotypes were designated accurately and the disorder was characterized, analysis of affected individuals led to the discovery of FOXP2. 

It is worth clarifying that FOXP2 has only been proven to affect the external aspect of language; it affects morpho-phonological processing¹but not comprehension and perception. Auditory processing, and the interpretation of words into meanings are cognitive processes that occur in the mind, and cognitive scientists have not yet been able to define the relationship between the brain and mind¹1. Thus, while the process of speaking can be described in terms of anatomy and genetics, there are still many mysteries to explore when it comes to communication. How do we understand the meaning of what is said to us? How does the tone of the speaker enhance the meaning interpreted by the listener? How does the brain process learning a foreign language?  

Overall, language is a very intricate skill that we cannot take for granted. Language is not just a simple combination of letters; it is the combined effort of genetics, physical movements and cognition. Every time we speak, we are using our lungs and diaphragms. We are coordinating fine movement with our lips, and repositioning our tongues with every different sound. We are processing words and grammar in our minds as we finish verbalizing our ideas. Yet, we do so in an instant and without much reflection. Thanks to language, we can ask people for help, express care for our loved ones, and share our knowledge and passion with the world. 

References 

[1] Boeckx, C. (2013). Biolinguistics: forays into human cognitive biology. Journal of Anthropological Sciences, 91, 63-89. 

[2] Enard et al. (2002). Molecular evolution of FOXP2, a gene involved in speech and language. Nature, 418, 869-872. 

[3] Khadem-Vargha, F. Gadian, D. Copp, A. and Mishkin, M. (2005). FOXP2 and the Neuroanatomy of Speech and Language. Nature Reviews, 6, 131-138.