The structure, derivation selleckchem and evolution of language is given by the sequence (elements, concatenation, embedding). This sequence is both derivational and evolutionary, as each member of the sequence has the one(s) to its left as its logical and evolutionary prerequisite(s). Arguably, the sequence is the general principle by which language is structured and evolved. Starting with a limited set of signs, it then

expands the set, first by concatenating and, in later stages, also by embedding the signs. With the support of Jackendoff, 1999, Nowak et al., 2000, Diessel and Tomasello, 2005, Johansson, 2006 and Dessalles, 2006, we arrive at the following four-stage evolutionary scale of syntactic compositionality: (1) signs, (2) increased number of signs, (3) commutative concatenation of signs, (4) grammar (noncommutative concatenation of signs), resulting in semantic embedding (initially, words in phrases and sentences). The scale is hierarchical, i.e. selleck chemical at each stage the conditions stipulated by the previous stage(s) apply as well. We show how all these stages can be adaptive

per se (which could explain why they evolved), and argue that CARC and CCLI are preconditions for maintaining stages (2) and (3), respectively. A principal trait of the scale is its scope: up to the emergence of grammar. Differently from e.g. Dessalles, 2006, Jackendoff, 1999 and Johansson, 2006, we do not model stages beyond (4). Implications for ontogeny should not be taken as granted but our model predicts that children’s inventory of elementary verbal signs (not necessarily words, as children may confuse phrases with words) must

grow to reach a certain size Cyclic nucleotide phosphodiesterase before the concatenation starts. The model also predicts a (possibly unstable) stage of commutative concatenation preceding the noncommutative one. We thank James Hurford, Noam Chomsky, Michael Corballis, Haldur Õim, Kate Arnold, Kim Sterelny, Keith Stenning and the anonymous reviewers for their many helpful comments and suggestions. All remaining mistakes are our own. Erkki Luuk was supported by the target-financed theme No. 0180078s08, the National Programme for Estonian Language Technology project “Semantic analysis of simple sentences 2”, the European Regional Development Fund through the Estonian Center of Excellence in Computer Science, EXCS, and the Alexander von Humboldt Foundation. “
“Fig. 2 was incorrectly published in the original publication. The corrected figure is provided below. “
“The corrected Abstract for this article is given below: There is a widespread view that forest plantations with exotic species are green deserts, unable to sustain biodiversity. However, few studies have demonstrated that planted stands of exotic trees have a greater negative effect on the plant diversity of savanna vegetation.