31. What can we learn about the project from the last two paragraphs?
A. It is well received.
B. It needs to be more creative.
D. It takes ages to see the results.
C. It is highly profitable.
D
Human speech contains more than 2,000 different sounds, from the
common “m” and “a” to the rare clicks of some southern Africanlanguages.
But why are certain sounds more common than others? A ground-breaking,
five-year study shows that diet-related changes in human bite led tonew
speech sounds that are now found in half the world’s languages.
More than 30 years ago, the scholar Charles Hockett noted that speech
sounds called labiodentals, such as “f” and “v”, were more common inthe
languages of societies that ate softer foods. Now a team of researchers ledby
Damián Blasi at the University of Zurich, Switzerland, has found howand
why this trend arose.
They discovered that the upper and lower front teeth of ancient human
adults were aligned (对齐), making it hard to produce labiodentals, which
are formed by touching the lower lip to the upper teeth. Later, ourjaws
changed to an overbite structure (结构), making it easier to produce such
sounds.
The team showed that this change in bite was connected with the
development of agriculture in the Neolithic period. Food became easierto
chew at this point. The jawbone didn’t have to do as much work and so
didn’t grow to be so large.
Analyses of a language database also confirmed that there was a global
change in the sound of world languages after the Neolithic age, with theuse
of “f” and “v” increasing remarkably during the last few thousandyears.
These sounds are still not found in the languages of manyhunter-gatherer
people today.
This research overturns the popular view that all human speech sounds
were present when human beings evolved around 300,000 years ago. “The
set of speech sounds we use has not necessarily remained stable sincethe
appearance of human beings, but rather the huge variety of speechsounds
that we find today is the product of a complex interplay of things like
biological change and cultural evolution,” said Steven Moran, a memberof
the research team.
32. Which aspect of the human speech sound does Damián Blasi’s research
focus on?
A. Its variety.