ABSTRACT
The study of language development in the last few years is marked by in-depth collaborations of theoretical linguists and developmental psycholinguists. In this chapter I would like to briefly discuss some major motives for this interdisciplinary venture from the viewpoint of the linguist (Section 1); then I will examine in detail a concrete example illustrating the approach and the disciplinary payoff which can be expected. The case that the paper focuses on is the following: around the age of two, language learners typically produce main clause declaratives with the verbs in the infinitival form, an option that is not found in the target languages. I shall argue that root infinitives are truncated structures (Section 3); they arise as a consequence of the option of ‘stripping ofF external clausal layers, an option which is characteristic of early grammars, while being banned from adult systems under normal circumstances. The same option is also arguably responsible of other properties of the early systems, such as the Early Null Subject (see Chapter 11). A number of structural properties of root infinitives, as well as their cross-linguistic distribution, will be shown to be amenable to the truncation analysis in conjunction with plausible auxiliary hypotheses (Sections 2–4).
