This special issue takes up three major concerns that have been raised by the recursion-only hypothesis by Hauser et al. (2002). The first concern is how to test for recursion in experimental psychology: Since we cannot test humans on infinite sets of sentences and furthermore self-embedding in the sense of (1) is difficult for humans to process, how can recursion best be tested for? The second major concern is the role of recursion in linguistic theory: Is recursion an integral part of any syntactic structure building or is recursion better viewed as something on top of more basic structure building? Finally, the third major concern this issue addresses is the relation of recursion to the genetic and neural basis of language. Can recursion be separated from other parts of language in the genetic and neural domain?

This volume focuses on work that has its origin and motivation in formal linguistics and theory-driven research on the acquisition of grammar, and on this basis tries to establish links to language pedagogy, including students’ and teachers’ beliefs about what ‘grammar’ actually is. The contributions to this volume cover a wide range of empirical linguistic domains and concern aspects of morphosyntax, including word order, inflectional morphology, article systems, pronouns, compounding patterns, as well as orthography and students’ general beliefs about grammar.