This study investigated whether cross-linguistic differences in causal expressions influence the mapping of causal language on causal events in three- to four-year-old Swiss-German learners and Turkish learners. In Swiss-German, causality is mainly expressed syntactically with lexical causatives (e.g., ässe ‘to eat’ vs. füettere ‘to feed’). In Turkish, causality is expressed both syntactically and morphologically – with a verbal suffix (e.g., yemek ‘to eat’ vs. yeDIRmek ‘to feed’). Moreover, unlike Swiss-German, Turkish allows argument ellipsis (e.g., ‘The mother feeds [∅]’). Here, we used pseudo-verbs to test whether and how well Swiss-German-learning children inferred a causal meaning from lexical causatives compared to Turkish-learning children tested in three conditions: lexical causatives, morphological causatives, and morphological causatives with object ellipsis. Swiss-German-learning children and Turkish-learning children in all three conditions reliably inferred causal meanings, and did so to a similar extent. The findings suggest that, as young as age 3, children learning two different languages similarly make use of language-specific causality cues (syntactic and morphological alike) to infer causal meanings.

Analyzing the development of the noun-to-verb ratio in a longitudinal corpus of four Chintang (Sino-Tibetan) children, we find that up to about age four, children have a significantly higher ratio than adults. Previous cross-linguistic research rules out an explanation of this in terms of a universal noun bias; instead, a likely cause is that Chintang verb morphology is polysynthetic and difficult to learn. This hypothesis is supported by the fact that the development of Chintang children's noun-to-verb ratio correlates significantly with the extent to which they show a similar flexibility with verbal morphology to that of the surrounding adults, as measured by morphological paradigm entropy. While this development levels off around age three, children continue to have a higher overall noun-to-verb ratio than adults. A likely explanation lies in the kinds of activities that children are engaged in and that are almost completely separate from adults' activities in this culture.

In this paper we propose a method for characterizing development in large longitudinal corpora. The method has the following three features: (i) it suggests how to represent development without assuming predefined stages; (ii) it includes caregiver speech/child-directed speech; (iii) it uses statistical association measures for investigating co-occurrence data. We exemplify the implementation of these proposals with data on the acquisition of the patterning of tense and grammatical aspect of four Russian children. The method, however, is suitable for a wide range of other acquisition questions as well.

The goal of this research is to determine the relevant factors that aid in the acquisition of the perfective aspect in Russian. Results confirm the findings of previous research, which say that aspect is not learned as a uniform category, but rather interrelates with the acquisition of Aktionsarten. This study focuses on the factors responsible for the difference in the rate of the acquisition of two complementary Aktionsarten in the perfective aspect: telic verbs (verbs including a result/goal of the denoted event) and ingressive verbs (verbs including the beginning of the event).

Since the usage of Aktionsarten strongly depends on the surrounding discourse, two experiments that varied in their discourse complexity were conducted. One study looked at the production of isolated utterances (thirty-nine children aged 3;0 to 6;11) and the other study focused on complex texts (fifty-two children aged 3;0 to 6;11). It was found that while telics are used independently of discourse context, ingressives depend strongly on contextual information.

These results suggest that discourse complexity and narrative competence define the acquisitional process for ingressives, yet are irrelevant in the acquisition of telics.