Section 1


Outline of Human Phylogeny

Evolutionary Trees
and DNA

Brain Evolution

Hand and Bipedality

Section 2
Social and socio-
cultural systems

Primate societies

Social relations and the evolution of culture

Social relations, communication and cognition

Human socio-cultural patterns

Tools and symbolic behaviour

Palaeolithic Art

Contemporary hunter-gatherer art

Section 3
Ontogeny and symbolism

Editorial Introduction: Ontogeny & Phylogeny

The role of ontogenesis

Brain, cognition, and language

Early interaction and cognitive skills

Language and thought

Theories of symbolization
and development

Children's drawings and the evolution of art

Section 4
Language systems

Spoken language and
sign language

The gestural primacy hypothesis

Comparative cognition

Animal language and cognition

Language acquisition


The prehistory of grammar

Writing systems


Links Policy

Relevant Links

Spoken language and sign language

Margaret Deuchar

'Language' has been defined in three ways: by listing its 'design features'; its structural properties, particularly its 'rule-governed creativity'; and its uses or functions.

In terms of design features, spoken and signed languages differ trivially in terms of the latter's not using the vocal-auditory channel; but have been claimed to differ more significantly in the extent to which spoken language is composed of arbitrary signs, while sign languages are based on more iconic signs. This has led to an erroneous demotion of the status of sign languages. A more careful analysis shows that both types of language are comparable on this dimension in their contemporary forms, although there is some evidence that languages of both media have become more arbitrary over time. Similarly, structural analyses of both systems reveal they show a similar degree of 'duality of patterning', both below the structure of the word or sign, and above it at the level of grammar.

Children go through very similar stages in acquiring either system when it is the 'natural' language of their early environment, although at different rates. Initially sign language is learned earlier; but later this advantage diminishes. However, most deaf children learn sign language under unusual conditions, since most (c.90 per cent) do not have native signing parents. Such children are comparable to those 'learning' spoken creoles on the basis of pidgin inputs: features of their signing system are creations of the 'learners' themselves. This provides some support for Chomsky's contention that language acquisition is not heavily dependent on the nature of the linguistic input.

Creoles are languages which have developed out of pidgins into native languages. Structural similarities between spoken creoles and sign languages may reflect language universals. This has been claimed as supporting the existence of an innate language faculty that strongly constrains the properties of individual languages. An alternative argument is that language structure is more constrained by functional demands, structural characteristics resulting as compromises between the need for a usable language to be clear, cognitively processable, 'quick and easy', and expressive. These two theories may well complement each other: the initial stages of language (both developmentally and historically) might be accounted for in terms of what is biologically given, whereas later language may change more in response to its expanding uses [Eds].