Despite contrary research findings, many laypeople still claim that starting second language (L2) instruction early yields linguistic advantages. This assertion is again undermined by a 5-year longitudinal study conducted in Switzerland testing the English language skills of 636 secondary-school students who had all learned Standard German and…

We present three statistical methods for causal analysis in life course research that are able to take into account the order of events and their possible causal relationship: a cross-lagged model, a latent growth model (LGM), and a synthesis of the two, an autoregressive latent trajectories model (ALT). We apply them to a highly relevant…

This study examines the impact of L2 literacy on the development of writing proficiency in the L3, as related to age of onset (AO) of instruction, as well as the effects of AO on ultimate L3 attainment at the end of the period of normal schooling. Using longitudinal data for the same student cohort (200 Swiss learners of English) at the beginning…

In this paper, we discuss the problem of articulation between levels in the educational system, as the transition from a rather more communicative, content-based and holistic approach to English as a foreign language (EFL) teaching at primary level to more formal and explicit ways of foreign language (FL) teaching at secondary is often experienced…

The main goal of this paper is to analyze how the age factor behaves as an alleged individual difference (ID) variable in SLA by focusing on the influence that the learning context exerts on the dynamics of age of onset (AO). The results of several long-term classroom studies on age effects will be presented, in which I have empirically analyzed…

The study aims were to identify developmental trajectories of young children with autism and investigate their prognostic factors. The participants were 208 children, assessed first at the age of 5 years, followed longitudinally, and reassessed 3 years later. The children's clinical characteristics and the interventions received were recorded. The…

This special issue of the "Courrier," a journal for professionals concerned with issues related to the physical and psychological development of children, provides (1) an overview of 25 years of internationally coordinated research, (2) a selection of papers published by the research teams, and (3) a description of the teams and their…