This thesis explores the acquisition of functional categories from a neo-emergentist perspective (following Biberauer, 2011, et seq. and Biberauer and Roberts, 2015). The central proposal is that syntactic development is neither guided by a maturational program nor by innate categories. This line of thinking, which impoverishes Universal Grammar, is not just conceptually desirable (per Chomsky, 2005, et seq.), but enriches the explanatory power of the resulting theory in significant ways.
Firstly, the thesis presents a corpus study on ten children across five languages (Catalan, Italian, Spanish, German and Dutch) in the CHILDES database and it aims to probe the acquisition of the CP-, TP- and ‘Split CP’-domains. Two key generalisations reveal themselves from this investigation: whilst CP-structures emerge early (either simultaneously with, or less clearly, earlier than TP-structures), further internal elaboration within CP (a Split CP-domain) systematically emerges late. I argue that these empirical generalisations mean no extant theory of syntactic development assuming innate categories is adequate for this dataset. This is because the findings generate theoretically contradictory requirements: they show that some representation of the CP must emerge early, but it cannot be formally cartographic-type until a later stage. Their simultaneity is inherently incompatible with contemporary maturational (and continuity) approaches, which posit universal categorial sequences of fixed (often cartographic) granularity (e.g., Friedmann et al., 2021).
I interpret this result to stress the analytical strengths of ontologically more ‘flexible’ approaches, which pursue emergent categories and allow for changes in mental granularity (in the spirit of Song, 2019). In light of this, I develop a neo-emergentist account of the developmental patterns: the suggested framework probes Biberauer and Roberts’s (2015) emergent categorial hierarchy in the context of the acquisition of functional categories, whilst incorporating theoretical insights from Biberauer’s (2019) Maximise Minimal Means (MMM) model and Bosch’s (2022) adaptation within Dynamical Systems Theory. I show that this approach explains the patterns, and is both more theoretically parsimonious and more empirically restrictive relative to competing hypotheses, the latter of which tend to undergenerate or overgenerate.
The picture is completed by a formalisation of Biberauer and Roberts (2015) and categorial development, with the aid of the mathematical fields of Category Theory and Dynamical Systems Theory, adapting Ehresmann and Vanbremeersch’s (2007, 2019) model of Evolutive Systems to syntactic acquisition. I suggest that such a framework provides a useful interdisciplinary bridge with the study of evolving complexity in natural systems and that some of the theoretical and neo-emergentist results revealed by the corpus study are expected given the adoption of Evolutive Systems.
This empirical and theoretical exploration endorses the pursuit of the idea that syntactic categories (including cartographic ones) are emergent. Insofar as neo-emergentism is shown to meet the challenge presented by the empirical paradigm in this thesis, a comprehensive treatment of emergent category formation might begin to be within sight. All that is necessary for these otherwise problematic patterns to fall into place is the adoption of a neo-emergentist approach to categories, and the abandonment of maturation and innate categories. I maintain this is the way forward, with interesting ramifications following as a result.