Universal attractors in language evolution provide evidence for the kinds of efficiency pressures involved
Efficiency is central to understanding the communicative and cognitive underpinnings of language. However, efficiency management is a complex mechanism in which different efficiency effects—such as articulatory, processing and planning ease, mental accessibility, and informativity, online and offline efficiency effects—conspire to yield the coding of linguistic signs. While we do not yet exactly understand the interactional mechanism of these different effects, we argue that universal attractors are an important component of any dynamic theory of efficiency that would be aimed at predicting efficiency effects across languages. Attractors are defined as universal states around which language evolution revolves. Methodologically, in contrast to many previous, language-specific studies on efficiency, we approach efficiency from a cross-linguistic perspective on the basis of a world-wide sample of 383 languages from 53 families, balancing all six macro-areas (Eurasia, North and South America, Australia, Africa, and Oceania). We focus on the grammatical domain of verbal person–number subject indexes. We claim that there is an attractor state in this domain to which languages tend to develop and tend not to leave if they happen to comply with the attractor in their earlier stages of evolution. The attractor is characterized by different lengths for each person and number combination, structured along Zipf’s predictions. Moreover, the attractor strongly prefers non-compositional, cumulative coding of person and number. There are two domains in which efficiency pressures are most powerful: strive towards less processing and articulatory effort while increased lexicon complexity and memory costs are weaker efficiency pressures for this grammatical category given its order of frequency. Constant information flow overrides articulatory efficiency.