abstract,reversed about twenty-five years of research on vocal tract posi-
tioning based on the contours of the cranial base.Since Lieberman has
been an outspoken critic of anyone proposing different opinions from
his about the significance of cranial base variations,these preliminary
findings have extremely important implications for reconstruction of
linguistic sound production in fossil hominids.
Here,given all the emphasis on cranial base morphology and vocal
tract (upper respiratory) anatomy,we briefly review evidence about the
shape of the cranial base in a series of fossil hominids.Our work is similar
to Laitman’s,but we streamlined his approach by eliminating a couple
of measuring points,since both are often absent in crucial fossils.We cal-
culate the angle made between two lines that are used to approximate
the flexion of the cranial base (figure 14.2).One line is defined by a point
on the anterior palate between the two central incisors (prosthion) and
a point at the front of the foramen magnum (basion).The other line is
defined by the same point (basion) and another on the midline of the
basilar process (sphenobasion).The latter point roughly defines the
highest point of the vocal tract.Data for this angle are presented in table
14.1 and show the substantial difference between the flat cranial base of
chimpanzees,used here to illustrate the anatomical condition of a phy-
logenetically close relative known to lack the ability for the full range of
human sounds,and the flexed condition in contemporary humans,as223 Fossil Evidence for the Origin of Speech Sounds
Table 14.1
External cranial base angle in degrees (prosthion/basion/sphenobasion)
Mean Range
Recent modern humans (n =100) 46.3 31.5–68.6
Homo sapiens ancestor?
Skhul 5 48.4
Neanderthals
La Ferrassie 1 49.0
Shanidar 1 42.2
La Chapelle aux Saints 41.0
Saccopastore I 39.0
Teshik-Tash 38.5
Gibraltar 1 38.0
Early Homo from Africa
East Turkana 3,733 43.5
Olduvai hominid 24 38.0
Australopithecines
East Turkana 406 41.3
Swartkrans 47 29.5
Olduvai hominid 5 28.1
Sterkfontein hominid 5 17.6
West Turkana 17,000 8.3
Chimpanzees (n =50) 15.3 0.0–31.2