From Root Infinitive to Finite Sentence : The acquisition of verbal inflections and auxiliaries

Across languages, children in the earliest stages of syntactic development tend to omit overt markings of finiteness, such as verbal inflections and auxiliaries: when children use a verb, they use an infinitival form (e.g. Dutch) or a bare stem (e.g. English). From Root Infinitive to Finite Sentence focuses on the omission and gradual rise of finiteness in early child language. Spontaneous speech data from six Dutch children collected over a longer period of time provide the basis for a close examination of the small steps children take in the acquisition of finiteness. The primary question that this investigation tries to answer is: how do children access abstract grammatical properties of the target language? A second goal is to determine the universal as well as the language-specific aspects of the early non-finite stage in different child languages. Experimental data from Dutch and English two and three-year-olds make it possible to compare early non-finite clauses in a true root-infinitive-language like Dutch with those in a bare-stem-language like English. The acquisition of finiteness in Dutch involves learning of the morphological rule of inflection and its syntactic effect: verb movement. It is shown that these grammatical markings of finiteness are fairly hidden in the input of Dutch children and hence, are difficult to acquire. This results in a relatively long phase of use of nonfinite clauses (root infinitives) and the introduction of lexical markers of finiteness by Dutch children. Meanwhile, children build up the lexical knowledge required to derive grammatical finiteness. The author argues that the stepwise acquisition of finiteness from absent via lexical to grammatical finiteness explains semantic as well as structural changes in root infinitives, more specifically, the modal shift and the increase of dropped subjects. It is furthermore claimed that contrasts in the aspectual type of the verbs found in finite sentences, on the one hand, and root infinitives, on the other, follow from selection restrictions, cognitive immaturity and patterns in the input, but are independent from finiteness. The experimental results presented in this thesis clarify differences and similarities between Dutch and English, i.e. languages in which root infinitives contain true infinitives and bare stems, respectively. In both languages, root infinitives are unspecified default forms that can appear in a wide range of contexts and that characterise a pre-grammatical stage. A comparison between the Dutch and English experimental results reveals a cross-linguistic difference in the meaning of root infinitives: Dutch root infinitives are more often modally used than English root infinitives. This difference is accounted for by the Heterogeneous Set Effect: English root infinitives are a heterogeneous set, because they are indistinguishable from finite sentences with dropped inflection. Consequently, the set of English root infinitives contains 'real' non-finite clauses as well as finite clauses. The Heterogeneous Set Effect does not only explain why English root infinitives differ in meaning from Dutch root infinitives, but also why they contain stative predicates and wh-words (as opposed to Dutch root infinitives)