The speakers of tonal and non-tonal languages have genetic differences
FIVE years ago three well-known academics, including Noam Chomsky, wrote that the half-century old “interdisciplinary marriage” between biology and linguistics “has not yet been fully consummated.” That same year other scientists described the molecular evolution of a gene called FOXP2 which, when mutated, seems to cause people severe difficulty with grammar and articulation.
Another genetic condition that could shed light on the biology of linguistics is microcephaly (sometimes rudely called “pin-headedness”). It is linked to six genes, a spanner in the works of any of which leads the human brain to grow to only two-thirds of a pint in adults. That is less than a third of its normal volume. Those genes are alluring objects for studying the evolution of language because brain size has ballooned in people since their line split with that of their closest relatives. Even though birds sing and bees dance, nothing in nature matches a human’s richly complicated system of vocal communication. In short, language makes humans unique and genes active in the developing brain make language possible.