Genetics and Language Development
By Farhan Rahman
A word shared by over 31 languages? Huh, this seems strange to the average speaker. Interestingly enough, “huh,” although informal, is a universally understood term, proving how over time, languages have spread over large landmasses and have evolved over time. Yet, a pressing question that has yet to be looked deeper into is: How does our genetic makeup contribute to how we utilize or formulate language? How does language affect cognition in more higher order complex processes?
There have been various studies on how genetics has played a role in the formulation of language. To take a case in point, a study was done on an English family with verbal dyspraxia, a condition where children have difficulty moving their mouths to produce clear speech. With this disorder, there are no physical signs of damage to nerves or muscles, so genetics may be a possible avenue to examine. The study done on this disorder has shown that the condition results from a mutation in the FOXP2 gene, located on chromosome 7, affecting the language areas of the brain via several intermediate steps. Interestingly enough, FOXP2 is not a ‘language gene,’ but binds to another gene, CNTNAP2, reducing cellular response to the FOXP2 gene through downregulation. CNTNAP2 is involved in encoding neurexin, which connects neurons at synapses in the central nervous system and is crucial during the developmental stage of the human cortex at childhood.
Referencing what we already know about the FOXP2 gene, it was discovered that heterozygous disruptions of the FOXP2 gene cause a rare Mendelian speech and language disorder. There are also point mutations and chromosomal abnormalities that can result in speech impairment through verbal dyspraxia, for instance. Nonetheless, FOXP2 is not a significant cause of speech disorders, but ideally leads to the phenotypic expression of inability to communicate fluidly. The means in which the FOXP2 interacts with CNTNAP2 can be further studied on the genetic level to see in what way that this eventual speech impairment occurs. Such understanding may also highlight how we can execute gene therapy, helping to overcome language barriers. All in all, it is imperative that we consider alternatives such as gene therapy to re-mediate communication barriers.