Language in the world: properties and powers
Linguistic autonomy
The autonomy of language sounds
The same is true at the level of sounds (in spoken languages; the equivalent sub-system in sign languages is gestures). That is, there are limitations on sequences of phonemes: a system of such constraints is universal, but its manifestations differ across different languages, so that, for example, '[t]he sequence /pik/ is not a possible Twi word because it breaks the phonotactic rules of the language, whereas /mba/ is not a possible word in English though it is a word in Twi' (Fromkin et al. 2003: 323). Again, some researchers are exploring the possibility that these kinds of intra-language constraints do not require sophisticated inbuilt neural mechanisms to explain them, if the systems are 'self-organizing'. Thus de Boer (2000), for example, identifies probabilistic tendencies for the co-occurrence of certain pairs of vowels and of consonants within specific languages, as well as regularities in the way speech sounds are strung together into syllables. He claims that while functional explanations for these tendencies are plausible, so that speakers optimize sound production on articulatory, perceptual and cognitive criteria, these fail to explain the differences across languages, and it also remains unclear who is carrying out the optimization. His proposition is therefore that:
If none of the individual speakers carries out an explicit optimization of their sound system, but (near-)optimal sound systems are nevertheless found more frequently than nonoptimal ones, it is clear that the optimization must be an emergent property of the interactions in the population. (p.178)
De Boer has used computer simulations to test this theory, and concludes from these, whose outcomes replicate the patterns of cooccurrence of sounds found in human languages, that 'the characteristics emerge as the result of self-organization under constraints of perception, production and learning. The systems that are found can be considered attractors of the dynamical system that consists of the agents and their interactions' (pp. 193-5). Once a variety has such patterns, they can become partially self-perpetuating as boundaries between varieties, in that either the adoption of items from other varieties will entail modification of them in accordance with 'vowel harmony and other phonological constraints' or 'the difficulty of adaptation leads to the exclusion of foreign words from the phonological or morphological system of the borrowing language' (Thomas 1991: 57).
