Origin of language: Fossil and archeological evidencesJun Hong Kim

A few factsOldest evidence for written lan-

guage: about 6000 years ago, among relics of Sumerian civiliza-tion.

Speech allows us to communi-cate information at an exceeding rapid rate.

A few facts (cont.)Nonhuman primates do complex vo-

cal communications.◦From 1980’s, previous dichotomies be-

tween human and non-human primate language abilities have gradually broken down: voluntary vs. involuntary, referen-tial vs. indexical, graded vs. discrete, learned vs. unmodified.

However, no abstract content, no grammar, inflexible in incorporating new concepts

Teaching human language to chimp and gorilla: partially succeeded: Hundreds of words, spontaneous use of signs

However, they (such as Kanzi) are superior to their conspecifics in their ability to learn and use lan-guage.

Fossil EvidencesNo direct evidence! Because vo-

cal tract is made up of soft tissue. Moreover, the capacity for

speech is neither necessary nor sufficient for language.

Articulate speech: When? Proba-bly, early Homo.

EndocraniumLanguage center?

◦Broca’s area/ Wernicke’s area

Seem to better developed in early Homo◦Endocast of KNM-ER 1470: signs of Broca’s

area (Tobias 1981, Falk 1983), Expansion in prefrontal cortex (Falk 1983)

◦Brain lateralization: right-handedness sug-gest-ed by stone-tool knapping (Toth 1985).

• Most endocasts are incomplete or distorted. • Homologues of Broca’s and Wer-nicke’s area are present in chim-panzee brain.

Criticism

Basicranium flexionLieberman and his associates (1972,

1991) proposed that the shape of cra-nial base correlates with the size of pharynx and the position of larynx.

Descent of larynx during development enables human adult to make discrete sounds (such as [i], [u], [a],[k],[g]) by making vocal tract curved and large.

From reconstructed hominid cast, they rebuilt laryngeal structures, estimated sound-production capability.

Source: Klein (1999)

They concluded that numerous hominid fossil, especially Nean-derthals, did not have full linguis-tic ability.

CriticismIt is impossible to make certain parts

from the original cast (Burr 1976).The basicranial flexion of some early

Homo are within the range of that of modern human (Frayer and Nico-lay 2000).

Homo ergaster may be first hominid who is able to do a degree of articulate speech.

Source: Frayer and Nicolay (2000)

Gibson and Jessee (1994) failed to find con-sistent association be-tween features of cranial base and laryngeal position in a col-lection of modern Americans from Texas.

Langdon (2005) argues that spe-cialized neurological control over the necessary muscles might be more important than basicranial flexion. Red deer have lowered the pharynx to make deeper and louder calls, but they cannot do complex speech.

More importantly, a narrower range would not have precluded spoken language.

Size of hypoglossal canalHypoglossal canal may be additional ev-

idence for speech. Responsible for inner-vation of the tongue. (Kay et al. 1998)

Australopithecines and early Homo are within the ape range.

Size of hypoglossal canal (cont.)The canal size is a poor indicator

of nerve diameter because there are numerous non-human pri-mate taxa that have hypo- glossal canals within the modern human size range (DeGusta et al. 1999).

Size of spinal cord and respira-tory systemLarge diameter of neural canals

may facilitate increased motor control of the diaphragm and in-tercostal muscles for the control of breathing during speech (Mac- Larnon and Hewitt 1999).

Rib cage◦Funnel shape: chimp and Australop-

ithecines◦Barrel shape: from Nariokotome boy

(WT-15000), dated 1.6 mya.

Development of external nose has implication for speech sounds, such as some consonant produced by nasal resonance (e.g. [n]).From early Homo

Hyoid bone

Kebara Neanderthal hyoid bone has com-pletely modern shape. Accordingly, “Nean-derthals appear to be anatomically capable of competent speech (Arensberg et al. 1990).”

In human, hyoid bone is not directly involved in speech, although in apes it is important in some vocalization. More importantly, there are only two intact hyoid bones of hominid and their morphology is completely modern (Frayer and Nicolay 2000).

Archeological EvidenceAccording to archeological evidence,

only fully modern humans after 50kya possessed fully modern language ability.◦Tool making and language are sequential

behavior◦Complex societies need arbitrary imposition

of standards and patterns, which would be impossi- ble without language.

◦Artistic expression: introspective conscious-ness.

◦Symbolic behavior: use of mineral pigments, manufacture of crudely shaped figurines and carving marks on stone or bone

Why language? – Selective pres-sure1. Lieberman (1984): Tradeoff be-

tween inhalation and phonation2. Byproduct of bipedalism: basi-

cranial flexion facilitated head balance in a bipedal posture.

3. Byproduct of climate adaptation: reshaped upper respiratory tract.

ConclusionPace of language evolution:

gradual or abrupt?When? Early Homo? Or, anatomi-

cally modern human?The use of language, as opposed

to the capacity for it, may or may not have appeared at the same time.